adapt-pt · this publication is a supplement to adapt-pt program manual for the analysis and design...

ADAPT-PTFOR

POST-TENSIONEDFLOOR SYSTEMS AND BEAMS

Supplement to ADAPT-PT Manual

Copyright 2000

STRUCTURAL CONCRETE SOFTWARE SYSTEM

Dr. Bijan O. AalamiStructural Engineer

Emeritus Professor, San Francisco State University

Consulting Company Member

E-mail: [email protected] website: http://www.AdaptSoft.com1733 Woodside Road, Redwood City, California, 94061, USA, Tel: (650) 306-2400 FAX: (650) 364-4678

POST-TENSIONINGINSTITUTE

http://www.AdaptSoft.com

This publication is a supplement to ADAPT-PT Program Manual for the analysis and designof post-tensioned buildings and parking structures. The focus of this supplement is on thegeneration of input data and the execution of the program. The theoretical background tothe program, verification of the results, description of the printout, and many other featuresof the program are contained in the Program Manual. The Program Manual can be obtainedfrom: ADAPT Corporation, 1733 Woodside Rd, Suite 220, Redwood City, Ca 94061, E-mail:[email protected].

Copyright © 2000By ADAPT Corporation

First Edition, First Printing, November 2000Printed in U.S.A.

ISBN:0-9674567-1-1

All Rights Reserved. This publication or any part thereof may not be reproduced in any formwithout the written permission of ADAPT Corporation.

ADAPT Corporation, 1733 Woodside Road, Suite 220, Redwood City, California 94061, USATel: (650) 306 2400; Fax: (650) 364 4678; E-mail: [email protected]; www.adaptsoft.com

http://www.adaptsoft.com

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CONTENTS

INPUT DATA AND RESULTS1.0 INTRODUCTION ................................................................................................................................ 1-11.1 BASIS OF DESIGN ........................................................................................................................... 1-11.2 POST-TENSIONING DESIGN APPROACHES ................................................................................... 1-11.3 GEOMETRY OF THE MODEL ............................................................................................................ 1-41.4 STRUCTURAL MODELING ............................................................................................................... 1-71.5 LOADING ........................................................................................................................................ 1-161.6 MATERIALS .................................................................................................................................... 1-211.7 SHEAR CALCULATIONS ................................................................................................................. 1-331.8 DEFLECTIONS ................................................................................................................................ 1-361.9 OUTPUT OPTIONS ......................................................................................................................... 1-371.10 POST-PROCESSORS ..................................................................................................................... 1-41

PROGRAM EXECUTION2.0 GENERAL .......................................................................................................................................... 2-12.1 OVERVIEW........................................................................................................................................ 2-12.2 THE MAIN PROGRAM WINDOW ...................................................................................................... 2-22.3 INPUT EDITOR .................................................................................................................................. 2-52.4 GRAPHICAL DISPLAY OF INPUT GEOMETRY .............................................................................. 2-282.5 PROGRAM EXECUTION ................................................................................................................. 2-322.6 VIEWING AND PRINTING OUTPUT ................................................................................................ 2-442.7 PRINCIPAL OUTPUT FILES............................................................................................................ 2-482.8 SAVING PROJECTS........................................................................................................................ 2-492.9 TENDON SELECTION MODE .......................................................................................................... 2-51

PT SUMMARY REPORT3.0 PT SUMMARY AND POST-PROCESSORS ..................................................................................... 3-13.1 PT SUMMARY REPORT .................................................................................................................... 3-33.2 INITIAL STRESS ANALYSIS ........................................................................................................... 3-113.3 LATERAL ANALYSIS....................................................................................................................... 3-273.4 FRICTION AND LONG TERM LOSSES POST-PROCESSOR ......................................................... 3-713.5 USER STRESS COMBINATION ...................................................................................................... 3-93

APPENDIXA.1 REFERENCES.................................................................................................................................. 3-94

ACKNOWLEDGMENTS

The valuable contribution of Ms. Gail Kelley, Civil Engineer,Washington, DC, in the preparation of this publication isrecognized.

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Slab Band Using Unbonded TendonsSan Francisco Bay Area, California

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ADAPT INPUT DATA AND RESULTS

LIST OF CONTENTS

1.0 INTRODUCTION .................................................................................................... 1-1

1.1 BASIS OF DESIGN ................................................................................................ 1-1

1.2 POST-TENSIONING DESIGN APPROACHES ..................................................... 1-11.2.1 FINAL EFFECTIVE FORCE DESIGN .......................................................... 1-21.2.2 SYSTEM BOUND DESIGN .......................................................................... 1-31.2.3 DESIGN OPTIONS ....................................................................................... 1-3

1.3 GEOMETRY OF THE MODEL ............................................................................... 1-4

1.4 STRUCTURAL MODELING .................................................................................. 1-71.4.1 NUMBER OF SPANS................................................................................... 1-71.4.2 STRUCTURAL MODELING OF SLABS ....................................................... 1-7

Unit strip modeling ........................................................................................ 1-8Tributary Modeling ........................................................................................ 1-8

1.4.3 DROP CAPS AND DROP PANELS FOR TWO-WAY SLABS ...................... 1-81.4.4 BEAMS NORMAL (TRANSVERSE) TO DIRECTION OF FRAME .............. 1-101.4.5 SLAB BANDS (WIDE SHALLOW BEAMS)................................................ 1-101.4.6 EFFECTIVE FLANGE WIDTH .................................................................... 1-111.4.7 HAUNCHED BEAMS ................................................................................. 1-111.4.8 COLUMN GEOMETRY AND END CONDITIONS ....................................... 1-111.4.9 WIDTH OF SUPPORT FOR MOMENT REDUCTION.................................. 1-131.4.10 END-SUPPORT CONDITIONS.................................................................. 1-141.4.11 INTERIOR SUPPORT CONDITIONS........................................................... 1-14

1.5 LOADING ............................................................................................................. 1-161.5.1 NUMBER AND CLASSES OF LOADING ................................................... 1-161.5.2 TYPES OF LOADING ................................................................................. 1-161.5.3 LOAD SKIPPING (PATTERN LOADING) .................................................... 1-201.5.4 LOAD COMBINATIONS.............................................................................. 1-21

1.6 MATERIALS ......................................................................................................... 1-211.6.1 CONCRETE ............................................................................................... 1-221.6.2 POST-TENSIONING ................................................................................... 1-221.6.3 TENDON PROFILE .................................................................................... 1-221.6.4 MILD REINFORCEMENT (PASSIVE REINFORCEMENT) ......................... 1-26

1.7 SHEAR CALCULATIONS.................................................................................... 1-331.7.1 SHEAR CHECKS FOR ONE-WAY SLABS AND BEAMS .......................... 1-331.7.2 PUNCHING SHEAR CHECK FOR TWO-WAY SLABS ............................... 1-33

1.8 DEFLECTIONS .................................................................................................... 1-36

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ADAPT INPUT DATA AND RESULTS

1.9 OUTPUT OPTIONS ............................................................................................. 1-371.9.1 RESULTS REPORT ................................................................................... 1-371.9.2 RESULTS GRAPHS ................................................................................... 1-401.9.3 PT SUMMARY REPORT ............................................................................ 1-41

1.10 POST-PROCESSORS ......................................................................................... 1-411.10.1 FRICTION AND LONG TERM LOSSES ..................................................... 1-411.10.2 INITIAL ANALYSIS ...................................................................................... 1-431.10.3 LATERAL ANALYSIS ................................................................................. 1-44

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ADAPT INPUT DATA AND RESULTS Chapter 1

1.0 INTRODUCTION

This booklet provides an overview of the factors which govern the design of a post- tensionedmember with particular emphasis on the algorithms used in ADAPT. It also discusses the outputoptions. Chapter 4 of the Software Manual provides further details on the design algorithms.

1.1 BASIS OF DESIGN

A conventionally reinforced concrete slab is typically designed for strength (ultimate moment) require-ments. The design consists of selecting a slab thickness, concrete strength, and area of reinforcementwhich provide the required moment capacity. Serviceability (crack and deflection control) is ad-dressed by limiting the span to depth ratios and ensuring calculated deflection are within acceptablelimits.

Post-tensioned slabs are designed for both strength and serviceability requirements, however. Thepost-tensioning is usually designed to satisfy serviceability requirements by limiting stresses underservice loading. Nonprestressed reinforcement is added to achieve the strength requirements ifnecessary.

A good design optimizes the slab thickness, the beam widths and depths, the amount ofpost-tensioning, and the amount of mild reinforcement to arrive at a solution that complies with thegoverning codes. A design typically proceeds as follows:

• Determine the design criteria based on code requirements and additional site or struc-ture specific requirements;

• Analyze the structure;• Design the structure;• Select the post-tensioning based on stresses;• Add mild steel if necessary for the ultimate moment;• Check shear and deflections; and,• Adjust the design criteria if necessary and repeat the analysis.

The initial selection of design criteria and subsequent adjustments are of prime importance for anoptimum design. Having a good understanding of the design criteria is essential to being able to designefficiently. Specific design criteria will depend on the project but will typically include requirementsfor minimum cover over both post-tensioning cables and mild steel reinforcement, minimum averageprecompression and minimum and maximum percentages of dead load to balance. Additional designcriteria include material strengths, load factors and tendon profiles.

1.2 POST-TENSIONING DESIGN APPROACHES

There are two common approaches to the design of post-tensioned structures: the final effectiveforce approach and the system bound approach. The primary difference between the two ap-proaches is the way that prestress losses are handled.

Prestress losses include both immediate and long-term effects. There is a stress loss due to frictionbetween the strand and its sheathing or duct during stressing. There is also a small loss of elongation

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when the wedges are seated in the anchorage device. These immediate losses are jointly referred toas “friction and seating losses”.

Long-term effects result from creep and shrinkage of the concrete, elastic shortening of the concreteand stress relaxation in the prestressing strands. Strictly speaking, elastic shortening is an immediatephenomenon but it is grouped with the long-term losses since it is calculated in a similar manner. Theforces in the tendons after all stress losses have taken place are referred to as the final effectiveforces.

1.2.1 Final effective force design

The final effective force approach is typically used in situations where the structural designer isdifferent from the post-tensioning supplier and the design is done before the supplier isselected. The specifics of the post-tensioning system are thus not taken into account duringdesign. This is the most common design approach in the US and Canada.

The outcome of a final effective force design is the final effective post-tensioning force in eachspan and the tendon profile. The tendon profile is specified by indicating the height of thecenter of gravity of the strand (cgs) at critical locations. Hardware dependent parameterssuch as friction coefficients, relaxation of the strand and seating loss are considered during theshop drawing stage, independently of the design. Shop drawings prepared by the supplierare normally submitted to the structural engineer for review for compliance with the designconcept. The post-tensioning supplier determines the number of strands required based onthe system being used and provides information on stressing and elongations.

The sequence of steps in this type of design is as follows:

(i) The problem definition is formulated. This includes establishing:

• the geometry of the structure (dimensions);• the loading; and,• design criteria.

(ii) An analysis is done to determine both the post-tensioning and the supplementarymild reinforcement required at each location. The results are shown on the struc-tural drawings with the post-tensioning expressed in terms of final effective forces.Jacking forces, strand elongations and friction loss calculations are not shown on thestructural drawings.

(iii) Shop drawings are prepared by the post-tensioning supplier, based on the structuraldrawings. The shop drawings show the number of strands required, the layout ofthe strands, and the expected elongations. Immediate and long-term stress lossesare calculated according to the parameters of the post-tensioning system. The post-tensioning supplier must submit calculations for the friction and long-term stresslosses along with the shop drawings, in order to demonstrate that the number ofstrands shown supply the required post-tensioning forces.

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In monostrand construction it is common practice for post-tensioning suppliers to use reason-able, assumed average values for final effective forces rather than doing friction calculationsfor each tendon. Even though the hardware from different suppliers may be slightly different,the assumed values for final effective forces are often the same. If two suppliers assume thesame final effective forces, their tendon layout will be very similar.

1.2.2 System bound design

The system bound approach, also referred to as variable force design, allows for full variationof force along the length of tendons. In this approach, the change in post-tensioning due tostress losses is integrated into the calculations during design. The objective during design isto determine the number of strands required at each location.

The system bound approach is common in Europe and many other parts of the world. It isgenerally used when the post-tensioning supplier and the parameters of the system are knownand can be incorporated into the design. In some cases, the engineer may base the design onan arbitrarily selected post-tensioning system and allow the supplier to redesign the project ifthe system selected has parameters that are significantly different from those originally used.

The sequence of steps in this type of approach is as follows:

(i) Select a post-tensioning system and determine the tendon layout, including the planlocations and vertical profiles. Determine which end(s) of the tendons will bestressed.

(ii) Based on the geometry and parameters selected for the tendons, determine thelong-term stress losses, immediate stress losses and effective forces along the lengthof the tendons.

(iii) Analyze the structure with the balanced loading which results from the specifiedtendon layout. If necessary, make adjustments to the tendon profiles or the numberof strands provided for a given tributary. Rerun the analysis to determine how thesechanges affect the design.

The outcome of the design, including the number and location of the strands, friction losses,long-term losses and the elongation of each strand is shown on the structural drawings. Thestress losses thus form part of the structural calculations. Other than the tendon supportlayout, very little additional information is required on the shop drawings.

1.2.3 Design Options

Allowance for prestress losses is an integral part of any post-tensioning design. ADAPTsupports both the final effective force and system bound approaches. If the final effectiveforce approach is used, the Friction and Long-term Loss Post-processor can be used togenerate the information required for shop drawings. The post-processor is run at thecompletion of the analysis.

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1.3 GEOMETRY OF THE MODEL

The ADAPT post-tensioning software system can handle a wide range of structures includingone-way slabs, mat foundations, two-way slabs with drop caps and/or drop panels, waffle slabs, panjoists and a variety of beam designs. For two-way slabs, the Equivalent Frame model, as recom-mended in Chapter 13 of ACI 318, can be used.

The design algorithm used in ADAPT is based on a single story slab and/or beam frame with sup-ports above and/or below the slab or beam. The frame consists of one line of supports with theirassociated tributary widths. A simple example of frame modeling is shown in Fig. 1.3-1.

FIGURE 1.3-1

Span lengths are measured from support centerline to support centerline, also referred to as systemlines. The frame line runs from middle of support to middle of support in the direction of the frame.

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Figure 1.3-2 shows the definitions of left and right in the direction of the frame and transverse to theframe. It also shows the positive directions of applied loadings, span actions and column moments.

FIGURE 1.3-2

The parameters required to model the frame include the span lengths, the cross-sectional definition ofthe slab/beam in each span, and the details of the slab/beam supports. The cross-sections available inADAPT are shown in Fig. 1.3-3. Note, however, that the I-section and extended-T section are onlyavailable when doing segmental input.

A span which has a uniform cross-section is referred to as prismatic. Prismatic beams and slabs withor without drop caps and panels are typically modeled via the conventional input mode. The userinputs the span lengths, slab or beam width and depth, and whatever other dimensions are required todefine the geometry of the frame.

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FIGURE 1.3-3

A span with a non-uniform cross-section, i.e. a haunched beam or a slab where the tributary widthchanges within a span, is referred to as nonprismatic. Nonprismatic spans are modeled by breakingthe slab into segments and using the segmental input mode. A segment is a section of span in thedirection of the frame. Up to seven segments can be defined for each span and each segment canhave a different cross-sectional geometry. Complex beam and slab geometries with nonstandardsupport conditions can be readily modeled with segments. Segments can also be used to modelchanges in the tributary width and steps at the top or bottom of the slab/beam. All changes in thecross sectional geometry of a member are rigorously accounted for in ADAPT when calculating therelative stiffness of the various frame members.

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1.4 STRUCTURAL MODELING

1.4.1 Number of Spans

Up to twenty spans plus one cantilever at each end can be entered for a frame; this should besufficient for almost any structure. If a frame has more than twenty spans, it can be divided insections by modeling the first twenty spans and fixing the right support. The remaining spansare then modeled with a second section that has the left support fixed. Unless the structure issymmetrical enough that no rotation would be expected over the support modeled as fixed,the results for the end spans will be incorrect. To get accurate values, at least three spansshould be overlapped.

1.4.2 Structural Modeling of Slabs

The slab/beam geometry input covers only the typical region of a span, which in most cases isthe midspan region. Information on the geometry of drop caps, drop panels, and transversebeams is input when defining the supports.

Figure 1.4.2-1 shows the input screen for slab modeling. The dimensions required to modela slab consist of the span length, the slab depth and the tributary width. The tributary width iscomposed of left tributary (the portion of the tributary width that falls to the left of the frameline) and the right tributary (the portion that falls to the right of the frame line). The tributarywidth can vary from span to span but is assumed to be constant within a single span unlesssegmental input is used.

There are two methods of modeling slabs: Unit Strip input and Tributary input. Both meth-ods produce the same results, which method to use is a matter of user preference. Once amethod is selected however, it should be used consistently throughout a given project toavoid confusion. Note that the calculations and results are always shown in terms of the totaltributary width, regardless of the way the slab was modeled during data entry.

FIGURE 1.4.2-1

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Unit strip modeling

It is typically easiest to model slabs with the Unit Strip method. A unit strip is a strip parallelto the span with a width equal to or less than the total tributary width. Although the unit stripwidth is typically 12 in. or 1000 mm, any reasonable value may be used. The unit width hasno affect on the analysis as long as the total tributary width is modeled correctly.

The tributary is modeled by specifying a unit strip width along with left and right multipliers.The left and right multipliers (<−Μ and Μ−>) indicate the number of times the unit stripneeds to be multiplied to cover the left and right tributaries. The multipliers need not be wholenumbers.

As an example, suppose the tributary width for a given span was 12 ft with 6 ft- 6 in. to theleft of the frame line and 5 ft- 6 in. to the right of the frame line. If the unit width had beenentered as 12 in., the left width multiplier would be 6.5, the right width multiplier would be5.5.

If there are drop caps and/or drop panels, the strips closest to the column will not have aconstant cross-sectional geometry. The program automatically calculates any correctionsrequired for the drop cap and drop panel regions.

Tributary Modeling

In tributary modeling, the total tributary width is entered as the ‘b’ dimension. The widthmultipliers (<-M and M->) are used to indicate how much of the tributary falls on either sideof the frame line. The sum of the left and right multipliers should be one.

1.4.3 Drop caps and drop panels for two-way slabs

Drop caps and drop panels are treated by the program as defined in ACI 318, regardless ofhow they are entered. A thickened slab that extends one-sixth of the span or more towardthe next support is treated as a drop panel; otherwise the thickening is considered a dropcap. The distinction between drops and caps is only significant when calculating ultimatecapacity, however, the actual cross section of the slab and drop is used when calculatingstresses. The added stiffness due to both drop caps and drop panels is taken into accountwhen calculating the relative stiffness of the columns and slab.

Any support can have a drop cap and/or drop panel and the caps and panels at differentsupports can have different geometries. The screen for defining drop panels is shown in Fig.1.4.3-1. The screen for defining drop caps is shown in Fig. 1.4.3-2.

The lengths parallel to the frame, D1 and D2, and the widths left and right of the frame line,W1 and W2, are specified for both drop caps and drop panels. Drop panels may havedifferent depths, H1 and H2 on either side of the support. Drop caps must be of uniformdepth H, specified as the total depth from the top of the slab to the bottom of the cap.

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Drop caps and panels do not have to extend to both sides of the support, i.e. either of theD1,D2 dimensions and either of the W1,W2 dimensions can be zero. Note that on theResults Report, the widths W1 and W2 are combined and shown as the total width.

FIGURE 1.4.3-1

FIGURE 1.4.3-2

If a support has both a drop cap and a drop panel, the depth of the drop cap must be greaterthan that of the drop panel; the length and width of the drop cap must be less than or equal tothose of the drop panel. Geometries that do not fit these restrictions can be modeled usingsegmental input.

Drop caps and drop panels can only be specified when conventional input is used. If seg-mental input is used, drop caps and drop panels need to be defined as separate segments.In segmental input, the segments are analyzed according to their actual geometry for bothstresses and ultimate capacity; there is no distinction between drops and caps.

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1.4.4 Beams normal (transverse) to direction of frame

In conventional input, beams normal to the direction of the frame can be modeled as trans-verse beams. The schematics for defining transverse beams are shown in Fig. 1.4.3-2. Thedepth of the beam is specified as the total depth H measured to the top of the slab, the widthof the beam is specified as the width left and right of the system line. Note that the trans-verse beam option is not available in segmental input. In segmental input, the beam must beentered as a segment which extends to the right and left edges of the tributary.

1.4.5 Slab Bands (wide shallow beams)

Typically, when the supports of a uniform floor slab are such that the spans are substantiallylonger in one direction than the other, the longer span governs the slab thickness. In post-tensioned slab construction, the adverse effects of the longer span can be reduced if thetendons in the long direction are banded and placed with an increased drape to provideadditional upward forces.

Wide shallow beams (Fig. 1.4.5-1) are basically a thickening of the slab along the columnlines to allow this additional drape. In order for the bands not to be considered as supports,the two-way action of the floor system must be retained. Although there is no absolutemaximum value for the band depth h, localized stiffening of the slab to an extent that wouldsignificantly inhibit slab deformation must be avoided. The recommended dimensions are:h≤2t and b>3h.

FIGURE 1.4.5-1

Wide shallow beams (slab bands) are entered by defining the span as one with a T-section(Type 2) having a shallow depth and wide stem. Since wide shallow beams are a two-way

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slab configuration the entire tributary width is considered effective in resisting the load. Therequirements for one-way shear reinforcement (stirrups) do not apply.

1.4.6 Effective flange width

Cast-in-place concrete beams are usually designed assuming an effective flange width thatincludes a given amount of the slab on either side of the beam. Although ACI specifies theeffective flange width to use for non-prestressed beams (stem width plus 16 times the slabthickness for T-beams, stem width plus 6 times the slab thickness for L-beams at slab edges),determination of the effective flange width for prestressed beams is left to the judgment of theengineer.

By and large the ACI-318 specifications for non-prestressed beams are used for prestressedbeams. In stress computations the effective width of a prestressed beam is larger than that ofa non-prestressed beam of the same geometry however, due to the precompression. Stemwidth plus 24 times the slab thickness for T-beams and stem width plus 12 times the slabthickness for L-beams are also used.

In ADAPT, the effective beam width may be calculated automatically according to ACI-318or it may be input by the user. Note however that the automatic calculation is not strictly perACI 318 for L-beams (edge beams). ADAPT calculates the effective flange width for bothT- and L- beams as the stem width plus an overhang which is up to eight times the slabthickness on each side but not more than the tributary width.

1.4.7 Haunched beams

Haunched beams are modeled using segments to represent distinct steps. Each span can havea maximum of seven segments, normally three steps are used for each haunch. The step sizesand locations are determined by the user. Figure 1.4.7-1(a) shows an example of ahaunched beam with sloping faces, Fig. 1.4.7-1(b) shows how it could be modeled.

1.4.8 Column Geometry and End Conditions

The relative stiffnesses of the column and slab/beam elements in a frame are determined bythe respective cross-sectional geometries and the column connections. The schematics on thesupport geometry screen (Fig. 1.4.8-1) show the dimensions that need to be entered forcolumns:

D = Column/wall depth (dimension in the direction of the frame).B = Column/wall width (dimension perpendicular to the frame).Dc = Diameter of a circular column (circular columns are transformed into square

columns of the same cross sectional area for analysis).H1 = Height of column below, measured from center of slab to top of slab below.H2 = Height of column above, measured from center of slab to underside of slab

above.

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FIGURE 1.4.7-1

FIGURE 1.4.8-1

Column connections are specified via the column boundary conditions. There are threepossible boundary conditions: fixed, pinned and roller. Typically, the columns above andbelow the slab/beam are modeled as fixed at both ends. Although it is not possible to specifya degree of fixity, the column stiffness can be reduced by entering a column height that isgreater than the actual height. Reducing the column stiffness reduces the amount of momenttransferred to the column; this may increase the post-tensioning required for the slab or beam.

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It may be appropriate to reduce the column stiffness in some instances because of anticipatedcracking.

Although each of the boundary conditions is specified separately, if the near end of a columnis specified as pinned, the column is not included in the frame analysis. In this case, it doesnot matter what the far end boundary condition is set to or what is entered for the length ofthe column.

1.4.9 Width of Support for Moment Reduction

The analysis is based on centerline moments (moments at the center of the joints). Momentscan be reduced to the face of the supporting column or beam by selecting the ‘Reducemoments to face-of-support’ option during data input. For column-supported slabs andbeams, the support width is typically “D”, the dimension of the column in the direction of theframe; drop caps are usually ignored. In one-way slab systems, the width of the beam istypically used as the support width for the slab model. Note that the support width is usedonly to determine moment reduction; it has no effect on support fixity. Also, only the negative(support) moment is reduced, the midspan moment is not changed.

Figure 1.4.9-1 shows recommended support widths for several typical conditions.

FIGURE 1.4.9-1

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1.4.10 End-support conditions

The supports at either end of the frame can be specified as rotationally free (a regular endsupport) or rotationally fixed. Rotationally free supports occur when the slab/beam termi-nates over a wall, column or beam and is free to rotate. The amount of rotation is a functionof the relative stiffness of the column/wall support and the type of support connection (fixedor pinned).

Rotationally fixed end-conditions occur when the span is tied to a structure that is rigidenough to prevent rotation of the slab/beam at the connection. A typical example might be aslab tied to a stiff shear wall. ADAPT calculates the bending moment developed by the slab/beam at the connection and designs the reinforcement accordingly. A rotationally fixed end-condition can also be used to model half of a symmetrical, multi-span frame if there will be norotation over the support at the line of symmetry.

Note that if there is a cantilever at the right or left end of the span, the corresponding endsupport cannot be specified as rotationally fixed. Figure 1.4.10-1 shows the screen used forentering End Support Fixity, support widths and boundary conditions.

FIGURE 1.4.10-1

1.4.11 Interior support conditions

The different interior support conditions are shown in Fig. 1.4.11-1. Note that deflection atthe centerline of the support (the system line) is assumed to be zero for all of the conditionsshown. ADAPT does not include provisions for modeling column shortening or supportsettlement.

The differences between the support conditions lie in:

• The connection between the slab/beam and the supporting column or wall;• The width of support in the direction of the frame; and,

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• For two-way slabs, the torsional stiffness of beams transverse to the direction of theframe.

The support conditions in Fig. 1.4.11-1(a), (b) and (c) represent a moment connection to theslab/beam. Moment transfer between the slab/beam and the column is based on the relativestiffness of the columns and slab/beam.

The wall support condition in Fig. 1.4.11-1(d) also provides a moment connection with theslab/beam. In each of these cases, the slab or beam can be designed based on momentsreduced to the face of support. The support width is typically, but not necessarily, the widthof the column or wall in the direction of the frame.

FIGURE 1.4.11-1

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For a two-way slab modeled with the equivalent frame method, the torsional stiffness of anybeams transverse to the frame, Fig. 1.4.11-1(e), will affect the solution.

Figure 1.4.11-1(f) shows a wall with a release or slip joint. Slip joints are used to minimizerestraint to shortening in the direction of the slab. Although the joint does not allow fortransfer of moments to the support, the span moments can be reduced based on the supportwidth.

Figure 1.4.11-1(g) shows a knife-edge support. In this type of support, no moment istransferred to the support and the system line moments are not reduced for the slab/beamdesign.

1.5 LOADING

1.5.1 Number and Classes of Loading

Each span can have an essentially unlimited number of different loadings. Live loading (LL)and dead loading (DL) are entered by the user. Loading due to the post-tensioning is calcu-lated automatically by the program. This is discussed further in Chapter 4 of the SoftwareManual.

Dead loading consists of selfweight and superimposed dead load. The program can be setto calculate selfweight automatically, based on the structure’s geometry and unit weight. Theself-weight calculated for each segment will be listed on the output with the notation SW. Ifthe spans have been entered via the segmental input mode, each segment’s weight will becalculated according to its respective geometry. Spans input via the conventional input optionwill be divided into segments, if necessary, to account for drop caps and drop caps. Theuser may also suppress the selfweight computation and enter the selfweight manually.

1.5.2 Types of loading

ADAPT supports five types of loading:

• Uniformly distributed loading over the entire span (U);• Partial uniform loading over specific sections of a span (P);• Concentrated loading at given distances along span (C);• Applied moment at given distances along a span (M); and,• Line loading along part or all of a span (L).

The loading types are shown in Fig. 1.5.2-1. Other loading distributions can be modeled asa combination of these types.

Uniform and partial loadings are assumed to be uniformly distributed over the uppermostsurface of the member with a constant intensity per unit area. The user only needs to enterthe load intensity (k/ft2 or N/m2); ADAPT calculates the frame loading. If a span has been

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entered segmentally with different tributary widths, there will be a non-uniform load distribu-tion along the span.

FIGURE 1.5.2-1

Line loading is specified as a uniform magnitude in the direction of span; it is not affected bythe surface geometry of the member. Line loading can be applied to part or all of a span.

Figures 1.5.2-2 (mnl-rc11) and 1.5.2-3 (mnl-rc14) illustrate various loadings on a two-spancolumn supported slab. Figure 1.5.2-4 (mnl-rc10) illustrates the difference between partialand line loading.

Since the analysis is based on a plane frame model of the member, all loadings must be addedup and compiled in terms of loading along the frame line. ADAPT automatically calculatesthe frame loadings from the user input. Both the user input and the calculated frame loadings

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are shown on the output. The position of the loadings transverse to the frame does not enterinto the calculations; all calculations are done for moments and shears in the direction of theframe.

FIGURE 1.5.2-2

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FIGURE 1.5.2-3

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FIGURE 1.5.2-4

1.5.3 Load Skipping (Pattern Loading)

If load skipping (pattern loading) was specified, the program applies load selectively onvarious spans in order to obtain the maximum and minimum moments and shears.

In the general case, there are six loading patterns (Fig. 1.5.3-1). In case one, the full deadand live load is assumed to act on all spans. In cases 2 through 6, dead load is assumed toact on all spans but live load, multiplied by a skip factor, is only applied to certain spans. Theloaded spans are selected in order to generate the maximize moments over the supports andat midspan. The skip factor is specified by the user and is typically less than 1.

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Except for the British code where a proportion of dead loading is also skipped, load skippingonly applies to live loads. All of the live loads entered for a span are considered to actsimultaneously.

FIGURE 1.5.3-1

1.5.4 Load Combinations

There are three load combinations: a code-specified serviceability (service state) condition,the ultimate (strength state) condition and a user-specified combination that can be used tocheck stresses for some condition other than the service state.

ADAPT has default load combination values for each of the codes but the user may overridethese values. The moments and shears at each 20th point are multiplied by the load factorsand combined in order to get minimum and maximum values for the specified load combina-tions.

1.6 MATERIALS

The calculations in ADAPT are based on materials-specific parameters entered by the user. Thereare separate screens for the concrete, the post-tensioning and the mild steel reinforcement.

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1.6.1 Concrete

Figure 1.6.1-1 shows the screen for entering concrete parameters. Depending on the code,the concrete weight classification is used in shear and/or flexure calculations. The ultimatecreep coefficient is used in the calculation of long-term deflections. Typical values are be-tween 2 and 3.

Default values of the modulus of elasticity are calculated based on the concrete strength andthe appropriate code formula.

FIGURE 1.6.1-1

1.6.2 Post-tensioning

ADAPT can handle both grouted and unbonded post-tensioning systems. Tendon sizes,strand diameters and steel properties are specified by the user.

1.6.3 Tendon Profile

The tendon profile can be specified as either a:

• Simple/Partial Parabola;• Reversed Parabola; or,• Harp.

Figure 1.6.3-1 shows the general shape of these profiles. The balanced load associated witheach profile is shown in Fig. 1.6.3-2. Users may enter variations of the basic tendon profilesin order to obtain a wide range of different balanced loadings. Figure 1.6.3-3 shows theparameters used to define the tendon profiles. The horizontal distances are specified duringdata input; the vertical distances are specified during the analysis when the tendon heights areentered.

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FIGURE 1.6.3-1

FIGURE 1.6.3-2

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FIGURE 1.6.3-3

Horizontal distances are entered as ratios of the span length, i.e. setting X2 = 0.5 wouldindicate the midspan. For all three profiles, the X2 distance indicates the point to use as thelow point of the profile. For the reversed parabola, the X1 and X3 distances indicate thelocation of the inflection points. For the partial parabola and harped profiles, the X1 and X3indicate that the tendon should be laid flat (without profile) for a given distance from thecenterline of the adjacent support. Note that selecting a partial parabola profile and specify-ing X1 and X3 as zero generates a simple parabola.

The user may select the profile most suited for a particular project and each span can have adifferent profile. In most situations however, the default parameters provided by ADAPTshould be used. Unless the structural drawings specifically call out something different, theseare what will be used by the detailer doing the shop drawings.

Beams, and distributed tendons in two-way slabs are usually detailed as partial parabolaswith inflection points at L/10. Banded tendons in two-ways slabs are also usually detailed asparabolas. One-way slab tendons are actually laid out with a profile more like a partial

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parabola with a straight section over the supports running 6 to 12 in. past the beam on eitherside. The difference in the design produced by these two configurations is negligible how-ever.

Harped profiles are used for transfer girders and other situations where there are heavyconcentrated loads. The low point of the profile is usually specified to coincide with thelocation of the concentrated load. Although the schematics for a harped profile sometimeshow a sharp point at the low point, tendons cannot actually be bent in a sharp kink. The ‘A’parameter is used to modify the harped profile to account for the fact that the bend will begradual. It indicates that the tendon is assumed to be flat for a given distance either side ofthe low point.

FIGURE 1.6.3-4

Cantilevers are defined in a similar manner. Figure 1.6.3-4 shows the profile optionsavailable for a cantilever. The X distance shown for the partial parabola and harped profiles

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1.6.4 Mild Reinforcement (Passive Reinforcement)

ADAPT calculates the mild reinforcement required for both code-specified minimums andultimate moment (strength). The Results Rebar graph (Fig. 1.6.4-1 section 6) displays theamount of rebar required versus amount provided, based on the bar sizes selected by theuser and shown on the Results Report. The PT Summary report shows the length andposition of the bars (Fig. 1.6.4-1 sections 3, 4 and 5); it also provides the option of recalcu-lating the required steel with a different bar size than originally selected in the input data of theprogram.

indicates that the tendon should be laid flat for a given distance from the centerline of the firstinterior support. In many cantilevers however, particularly those that are short and lightlyloaded, the tendon is run flat for the entire cantilever. This would be indicated on the struc-tural drawings by showing the same height (typically the centroid of the section) for thetendon height at both ends of the cantilever.

The Results Report displays a value for the balanced loading (k/ft or kN/m) in the blockwhich shows the selected post-tensioning (Block 9.3). These are representative upwardforces obtained by dividing the total upward force between the inflection points by therespective span length. They are for reference only; the calculations are based on the actualbalanced loadings.

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ADAPT - STRUCTURAL CONCRETE SOFTWARE SYSTEM ADAPT-PT Version 6.06 Date: 7/13/00 Time: 11:29:11 AM File: PT_sup10

1- PROJECT TITLE PT_sup10 1.1 DESIGN STRIP Support Line 4 Current_plane

2 - MEMBER ELEVATION [ft] 8.40 18.37 27.00 18.27 25.25 15.54 0.65

3 - TOP REBAR

3.3 ADAPT selected

3.4 ADAPT selected 6#5X10' 1 11#5X14' 2 10#5X6' 3

11#5X16' 4 10#5X6' 5

10#5X14' 8 12#5X14' 9 6#5X6' 12

4 - TENDON PROFILE

4.2 Datum Line 4.3 CGS Distance [in] 4.5 Force

4.00 7.00 4.93 [190 kips]

7.00 7.00 1.50 [190 kips]

7.00 7.00 1.00 [190 kips]

7.00 7.00 1.00 [190 kips]

7.00 7.00 1.00 [190 kips]

7.00 4.00 1.50 [190 kips] 4.00

4.00 4.00 [190

kips]

5 - BOTTOM REBAR

5.3 ADAPT selected

5.4 ADAPT selected 6#7X18' 6 5#7X14' 7

3#7X16' 10 3#7X12' 11

4#7X2' 13

6 - REQUIRED & PROVIDED BARS 6.1 Top Bars [ in 2 ] required provided

6.2 Bottom Bars

max

max

0.0 3.3 6.6

1.7 3.4 5.1 6.8

1.84

0.00

3.72

0.00

6.27

6.47

3.59

0.00

3.70

3.53

2.00

0.00

1.80

1.84

FIGURE 1.6.4-1 REINFORCEMENT REQUIREMENT AND SELECTION

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FIGURE 1.6.4-2 CUT-OFF LENGTHS AND BAR EXTENSIONS

Figure 1.6.4-2 shows the screen used to determine the lengths of the mild steel (non-pre-stressed) reinforcement. If the mild steel requirement is governed by the code requirementsfor minimum steel, the lengths will be determined by the values entered for cut off lengths. Ifthe mild steel is required to supplement the post-tensioning for ultimate moment, the lengthwill be based on the point where steel is no longer required. In order to determine the pointwhere mild steel is no longer required, the program calculates an envelope of the moments at1/20th points along the member. The user specified extension (development length) is addedto all bar lengths.

In the common case the reinforcement for the code minimum requirements is positioned asshown in Fig. 1.6.4-3 with the lengths specified in the figure. In the general case, wherenonconventional loading can cause tension at the top of the field and/or bottom of supports,the layout and lengths for the minimum reinforcement are as shown in Fig. 1.6.4-4

FIGURE 1.6.4-3 MINIMUM REINFORCEMENT LENGTHS AND LAYOUTFOR COMMON CONDITIONS

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FIGURE 1.6.4-4 GENERAL CASE FOR MINIMUM REINFORCEMENT LENGTHS ANDLAYOUT

The Results Report lists in three tables the area of steel required and shown in Fig. 1.6.4-1along with the associated quantity and lengths of the bars. Table 1.6.4-1 is the list of therequired reinforcement both for serviceability and strength along with the governing value ineach case. Table 1.6.4-2 is a simple compilation of the bars selected to envelop the requiredvalues shown in the preceding table. The bars in this table are the same as they appear insections 3 and 5 of Fig. 1.6.4-1. Any discrepancies between the two is due to round offprocedure adopted in the program. For the American units bar lengths are expressed inmultiples of 6 inches. For SI and MKS units 20mm or 2 cm are used respectively. Table1.6.4-2 is the breakdown of the bars into spans according to Fig. 1.6.4-4. In this table thebars which straddle the support lines are reported in two parts, each referring to the span thepart associates with.

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TABLE 1.6.4-1: REQUIRED REINFORCEMENT

11.2.1 S T E E L A T M I D - S P A N T O P B O T T O M As DIFFERENT REBAR CRITERIA As DIFFERENT REBAR CRITERIA SPAN (in^2) <---ULT-----TENS--------> (in^2) <---ULT-----TENS--------> --1------2---------3-------4-------5-----------6---------7-------8-------9---- 1 .00 ( .00 .00 .00) .00 ( .00 .00 .00) 2 .00 ( .00 .00 .00) 6.41 ( 5.07 6.41 .00) 3 .00 ( .00 .00 .00) .00 ( .00 .00 .00) 4 .00 ( .00 .00 .00) 3.53 ( 2.67 3.53 .00) 5 .00 ( .00 .00 .00) .00 ( .00 .00 .00)

11.3.1 S T E E L A T S U P P O R T S T O P B O T T O M As DIFFERENT REBAR CRITERIA As DIFFERENT REBAR CRITERIA JOINT (in^2) <---ULT-----MIN---------> (in^2) <---ULT-----MIN---------> --1------2---------3-------4-------5-----------6---------7-------8-------9---- 1 1.84 ( .00 1.84 .00) .00 ( .00 .00 .00) 2 6.34 ( 6.34 1.94 .00) .00 ( .00 .00 .00) 3 6.22 ( 6.22 1.94 .00) .00 ( .00 .00 .00) 4 2.81 ( 2.81 1.83 .00) .00 ( .00 .00 .00) 5 3.70 ( 3.70 1.82 .00) .00 ( .00 .00 .00) 6 1.80 ( .00 1.80 .00) 1.84 ( .00 1.84 .00)

TABLE 1.6.4-2: BREAKDOWN OF REINFORCEMENTACCORDING TO SPANS

11.2.2 & 11.3.2 SELECTION OF REBAR SPAN ID LOCATION NUM BAR LENGTH [ft] AREA [in^2] --1----2-----3------4----5-------6---------7---------- 0 1 T 6 # 5 x 10'6" 1.86 ------------------------------------------------------ 1 2 T 11 # 5 x 15'6" 3.41 1 3 T 10 # 5 x 6'6" 3.10 ------------------------------------------------------ 2 4 T 11 # 5 x 16'6" 3.41 2 5 T 10 # 5 x 6'6" 3.10 2 6 B 6 # 7 x 18'6" 3.60 2 7 B 5 # 7 x 14'6" 3.00 ------------------------------------------------------ 3 8 T 10 # 5 x 14'0" 3.10 ------------------------------------------------------ 4 9 T 12 # 5 x 14'0" 3.72 4 10 B 3 # 7 x 16'0" 1.80 4 11 B 3 # 7 x 12'6" 1.80 ------------------------------------------------------ 5 12 T 6 # 5 x 6'0" 1.86 ------------------------------------------------------ 6 13 B 4 # 7 x 2'0" 2.40 ------------------------------------------------------ Notes: Bar location - T = Top, B = Bottom. NUM - Number of bars.

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For one-way spans, the minimum area of bonded reinforcement in both positive and negativemoment regions is 0.004A where A is the area between the flexural tension face and thecenter of gravity of the cross-section. The reinforcement required is independent of the steelyield stress and must be provided regardless of the magnitude of tensile stresses at serviceloads. Calculation of the area A must consider the T-beam effect, thus T-beams requiremore bonded reinforcement in negative moment regions than in positive moment regions.

For two-way flat plates, a minimum bonded reinforcement equal to 0.00075 Acf must beprovided at negative moment regions, regardless of the magnitude of the tensile stresses atservice loads. Acf is the cross-sectional area of the larger of the two slab/beam design stripsintersecting at a support. In accordance with ACI-318 requirements, a minimum of four barsare specified over the supports.

In two-way construction, bonded reinforcement is not needed in positive moment regionsunless computed tensile stresses at service loads exceed 2 f’c. When computed tensilestresses exceed 2 f’c, the minimum area of bonded reinforcement must be equal to or greaterthan Nc/0.5fy where Nc is the total tensile force in the concrete due to unfactored dead andlive load.

Where the required reinforcement is provided to meet strength demand, the following consid-eration should be observed in the length determination and layout.

• At interior spans, extend one-fourth of the bars computed for strength requirements tothe adjacent supports.

• At exterior spans, extend one-third of the bars computed for strength requirements tothe adjacent supports.

This consideration is left to the user to observe when the results of the program are trans-ferred to the structural drawings. Use Table 1.6.4-1 to determine if and how much of thelisted steel area is for strength requirements.

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TABLE 1.6.4-3a: LAYOUT OF TOP REINFORCEMENT 11.5.1 STEEL DISPOSITION - TOP BARS -------|----------- TOP STEEL -----------------| SPAN | ID LOCATION | NUM BAR LENGTH [ft]| --1----|--2------3-----|---4----5------6-------| 0 | 1 RIGHT | 6 # 5 x 5'0" | -------|---------------|-----------------------| 1 | 1 LEFT | 6 # 5 x 5'0" | 1 | 2 RIGHT | 11 # 5 x 7'6" | 1 | 3 RIGHT | 10 # 5 x 3'0" | -------|---------------|-----------------------| 2 | 2 LEFT | 11 # 5 x 7'0" | 2 | 4 RIGHT | 11 # 5 x 8'0" | 2 | 3 LEFT | 10 # 5 x 3'0" | 2 | 5 RIGHT | 10 # 5 x 4'0" | -------|---------------|-----------------------| 3 | 4 LEFT | 11 # 5 x 7'6" | 3 | 8 RIGHT | 10 # 5 x 6'6" | 3 | 5 LEFT | 10 # 5 x 2'0" | -------|---------------|-----------------------| 4 | 8 LEFT | 10 # 5 x 6'6" | 4 | 9 RIGHT | 12 # 5 x 7'6" . | -------|---------------|-----------------------| 5 | 9 LEFT | 12 # 5 x 5'6" | 5 | 12 RIGHT | 6 # 5 x 5'0" | -------|---------------|-----------------------| 6 | 12 LEFT | 6 # 5 x 0'0" | -------|---------------|-----------------------|

TABLE 1.6.4-3b: LAYOUT OF BOTTOMREINFORCEMENT

11.5.2 STEEL DISPOSITION - BOTTOM BARS

-------|-------- BOTTOM STEEL -----------------| SPAN | ID LOCATION | NUM BAR LENGTH [ft]| --1----|--2------3-----|---4----5------6-------| 2 | 6 CENTER | 6 # 7 x 18'6" | 2 | 7 CENTER | 5 # 7 x 14'6" | -------|---------------|-----------------------| 4 | 10 CENTER | 3 # 7 x 16'0" | 4 | 11 CENTER | 3 # 7 x 12'6" | -------|---------------|-----------------------| 6 | 13 LEFT | 4 # 7 x 2'0" | -------|---------------|-----------------------|

UBC requirement of (D + 0.25*L)

ADAPT can optionally calculate the mild steel required for one-way systems designedaccording to the Uniform Building Code (UBC). UBC, the code used in the western US,requires that the mild steel reinforcement be able to resist actions developed due to the deadloading plus 25% of the unreduced live loading. This requirement has not been included inthe International Building Code (IBC 2000) however, nor is it part of ACI-318. Since UBCis no longer to be continued, the application of (D + 0.25*L) will be automatically phasedout.

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1.7 SHEAR CALCULATIONS

1.7.1 Shear Checks for One-way Slabs and Beams

For one-way slabs and beams, ADAPT calculates the factored shears at 1/20th points alongeach span and checks the section for one-way shear. The vertical component of thepost-tensioning force is conservatively disregarded in calculation of the shear strength. Thehyperstatic shear from post-tensioning is included in the design shear force (Vu). If the shearstrength of the section is not adequate, ADAPT calculates the required stirrups. The govern-ing ACI equations and ratio of Vu/Vc at each 1/20th point are printed along with the spacingof the stirrups.

1.7.2 Punching Shear Check for Two-way Slabs

For two-way slabs, ADAPT calculates punching shear at each of the supports. ADAPTrecognizes five different conditions in the calculation of punching shear: interior columns, endcolumns, corner columns, edge columns and wall (continuous) supports. Figure 1.7.2-1shows these different conditions. The user does not need to identify the conditions of theindividual supports, ADAPT determines this automatically from the geometry of the problem.If the face of a column is less than seven times the slab thickness from the slab edge, thecolumn will be considered an end, corner or edge column. If a column extends for 80% ormore of the tributary width, it is considered to be a wall. No punching shear check is donefor a wall support since a two-way (punching) shear failure is virtually impossible.

The output lists the factored moments and shears at each support, the calculated stresses andthe ratio of the stresses to permissible values. Secondary effects due to post-tensioning areconsidered in the evaluation of the factored moments and shears.

At each joint, ADAPT checks the punching shear at the critical section associated with theface-of-support (referred to as CASE 1), and at the critical section from the first change insection if the span has a drop cap and/or drop panel (referred to as CASE 2). The higher ofthe two stress ratios governs the design and is shown on the printout. Figure 1.7.2-2 showsthe two sections where punching shear is checked.

Note that if the face of the column is less than seven times the slab thickness from the slabedge, ADAPT ignores any overhang and conservatively assumes that the face of the columnis at the slab edge (Fig. 1.7.2-3) . If the punching shear ratio reported by ADAPT is notsatisfactory at one of these columns, it may be worthwhile to check it with a manual calcula-tion, since the software assumptions are conservative for nonstandard cases.

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FIGURE 1.7.2-1

1 - 35


FIGURE 1.7.2-2

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FIGURE 1.7.2-3

1.8 DEFLECTIONS

The maximum deflections in each span and deflection-to-span ratios are listed for:

• Dead load;• Dead load and post-tensioning;• Dead load, post-tensioning and creep;• Live load; and,• Dead load post-tensioning, creep and live load.

Negative numbers indicate upwards deflection Note that the figure for dead-load only deflection isprimarily shown for reference since the structure would typically be shored until the post-tensioninghad been applied. Creep is calculated based on the creep factor input by the user; the creep factor is

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applied to the deflection due to dead load and post-tensioning in order to determine the long-termdeflections.

Deflection of Cracked Sections

Deflections are calculated based on the gross cross-sectional geometry of the section. Wherestresses exceed the code-specified modulus of rupture, ADAPT uses a bilinear moment-deflectionrelationship with a reduced moment of inertia to account for cracking. If cracking has been allowedfor, the deflections block of the Results Report will show an Ie/Ig ratio less than one.

1.9 OUTPUT OPTIONS

Output options include the Results Report, the Results Graphs and the PT Summary Report. Thereare a large number of formatting options and all reports and graphs can be viewed on the screenbefore printing. There are also four optional post-processors.

1.9.1 Results Report

The Results Report is organized into separate data blocks; the report for a given analysis canbe configured to include only the blocks required. A virtually unlimited number of differentreports can be printed by selecting different data blocks.

The major data blocks are as follows:

1. General Input - General design criteria such as tension and compression limits andminimum average precompression.

2. Input Geometry - All geometry information: span lengths, tributary widths, columnsizes and boundary conditions.

3. Applied Loading - Loading as entered by the user and as compiled by ADAPT intoframe loading.

4. Calculated Section Properties - Area, moment of inertia, Yb and Yt for each segment ineach span.

5. Dead Load Moments & Shears - Dead load moments at the left, midspan and right ofeach span, shears at the left and right of each span, reactions and column moments.Span moments are moments at the support centerlines.

6. Live Load Moments & Shears - Minimum and maximum live load moments at the left,midspan and right of each span, shears at the left and right of each span, reactions andcolumn moments. Span moments are moments at the support centerlines. If live loadingwas not skipped, the maximum and minimum span values will be the same.

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7. Moments Reduced to F.O.S. – Dead load and minimum and maximum live load mo-ments at left, midspan and right of each span, reduced to the face of support. Note thatonly the support moments are affected when you reduce the moment to face of support;the midspan moments are not changed.

8. Sum of Dead and Live Moments - Minimum and maximum combined dead and liveload moments at left, midspan and right of each span. Moments are combined accord-ing to the user specified load combination factors for serviceability checks (typically 1.0DL + 1.0 LL). Depending on what has been specified under Design Criteria, the spanmoments will be either centerline moments or moments reduced to the face of support.

9. Selected Post-Tensioning - This block has several subsections:

• User-selected tendon profile type and parameters.

• User-selected post-tensioning force in each span and heights of the tendon atcontrol locations; average precompression and average balanced loading in eachspan.

• Required minimum post-tensioning force (kips or KN) at the left, center and right ofeach span based on stress conditions and minimum P/A.

• Maximum compression and tension service stresses at the top and bottom of thesection at the left, right and center of each span.

• Post-tensioning balanced span moments, shears, reactions and column moments.Note that the post-tensioning actions are self-equilibrating; within the limits ofnumerical accuracy the reactions will sum to zero.

10. Factored Moments & Reactions - Factored design moments at the left, midspan andright of each span, secondary moments at the left, midspan and right of each span,factored reactions and factored column moments. If live load was skipped, minimumand maximum span moments, reactions and column moments are shown. Designmoments and secondary moments are either centerline or face of support moments,depending on what was selected during data input.

11. There are two data blocks for mild steel. Mild steel (No Redistribution) shows theamount of mild steel required if there is no redistribution of moments. Mild steel (Redis-tributed) shows the amount of mild steel required if limited redistribution of the momentsis allowed. The two blocks are selected independently; selecting both blocks allows theuser to see how the steel requirement changes when moments are redistributed.

Mild Steel Required (No Redistribution) - Areas of mild reinforcement required at thesupports and spans for code requirements and ultimate strength; selected size, numberand length of bars required.

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Mild Steel Required (Redistributed) - Redistributed design moments and redistributioncoefficients along with area of steel, size, number and lengths of required bars.

12. Shear Calculations -For two-way slabs, this block shows punching shear stresses, forone-way slabs and beams this block shows shear stirrup requirements.

13. Deflection Calculations - Maximum immediate and long-term deflections in each span.Allowance is made for cracking of the concrete section where applicable.

14. Friction and Long Term Loss (Tendon Selection) – This data block is only applicablewhen the analysis has been done using the Tendon Selection mode. In the TendonSelection mode, prestress losses are incorporated into the design.

Post-processor Results:

15. Initial Stress Calculations – The Initial Stresses option allows the user to calculatestresses for any load combination and compare them to allowable stresses for anyconcrete strength. The data block will show whether compressive stresses are withinacceptable limits and whether any additional mild steel is required.

16. Lateral Analysis – The Lateral Analysis post-processor allows the user to check thedesign for lateral moments. The data block will show whether any additional mild steelis required.

17. Friction and Long Term Losses – If the analysis is done using the Force Mode (FinalEffective Force approach), the Friction and Long Term Losses post-processor can beused to calculate prestress losses.

In addition to the data blocks listed above, the following detailed listings are stored inseparate files that can either be viewed in a wordprocessor or included on the ResultsReport.

• Listing of balanced loading at 1/20th points along the spans

• Listing of moments, shears and stresses at 1/20th points along the spans for deadload, live load (minimum and maximum values), balanced loading and secondaryreactions.

• Listing of post-tensioning required at 1/20th points along the spans

• Listing of tendon heights at 1/20th points along the spans

• Listing of rebar required at 1/20th points along the spans

With the exception of the balanced loading, the same information can also be viewedgraphically on the Results Graphs.

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Figure 1.9.1-1 shows the Report Output screen used to indicate which data blocks toprint. The detailed listings are selected by clicking on the Detailed Output tab andchecking the boxes for the desired listings.

FIGURE 1.9.1-1

1.9.2 Results Graphs

The seven Results Graphs show values at 1/20th points along each span. The graphs whichmay be viewed on the screen, printed or saved as either .DXF or .WMF files show:

• Bending Moments;• Shears;• Stresses;• Post-tensioning required/provided;• Tendon Height;• Deflections; and,• Rebar required/provided.

Figure 1.9.2-1 shows a Results Graph for Bending Moments due to dead load.

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FIGURE 1.9.2-1

1.9.3 PT Summary Report

The PT Summary module enables the user to generate a flexible and compact graphicalreport for each ADAPT run. The report summarizes all post-tensioning parameters, rebarrequirements, and shear checks from a computer run on a single page of output. The format-ted report may be viewed on the screen, then printed, saved as a Drawing Exchange (.DXF)file or copied to the Windows clipboard as a .CLP file.

The report is designed for professionals involved in the design, construction, or managementphases of a project who need a compact, readily accessible summary of the post-tensioningand mild steel requirements. It does not show analysis results, design actions or deflectioncalculations. This information is available on the Results Report and Results Graphs.

1.10 POST-PROCESSORS

The four ADAPT post-processors are:

• Friction and Long Term Losses;• Initial Stresses;• Lateral Analysis; and,• Stresses.

1.10.1 Friction and Long Term Losses

The information for the Friction and Long Term Losses post-processors is entered duringdata input. If the Force/Tendon Selection Friction Calculations button on the Criteria –Calculation Options screen is chosen, additional input questions will appear. Information forboth short- and long-term losses can be entered, alternatively long-term losses can be speci-fied as a lump sum value.

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Figure 1.10.1-1 shows the screen for entering Friction and Long Term Loss information.The values shown are typical for an unbonded system.

FIGURE 1.9.3-1

The analysis will determine the stress in the tendon at the left, center and right end of eachspan. It will calculate the average initial stress, total long-term losses and anchor set influencedistance. It will also calculate required elongations for both one and two-ended pulls. Theresults of the Friction and Long Term Losses post-processor can be included on the ResultsReport by checking the appropriate box on the Report Setup screen.

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FIGURE 1.10.1-1

The analysis generates a file called FRICTION.DAT which can also be viewed in awordprocessor.

1.10.2 Initial Analysis

The Initial Stress Analysis allows the user to determine if additional mild steel reinforcing isrequired for loading conditions other than what is assumed for the original analysis. The termInitial Stress Analysis is something of a misnomer, however; its applicability is not limited tothe initial stress condition. Stress checks can be performed for any loading, post-tensioning,or concrete strength conditions. Several stress checks may need to be performed for a givendesign.

The reinforcing steel calculated during execution of the original analysis is based on thespecified 28 day concrete strength, full dead load, full or skipped live load and final effectivepost-tensioning forces. The Initial Analysis option allows concrete strength to be specified asa ratio of the 28-day strength, post-tensioning to be specified as a fraction of the final effec-tive forces, and dead and live load to be specified as a percentage of the full load. The ratioscan be zero, one, greater than one or less than one.

Information for the Initial Stresses Analysis is entered via the Post-Processors item on theAction menu. Figure 1.10.2-1 shows the entry screen with typical values for checkingstresses at the time the tendons are stressed. At this time, the concrete strength is often 0.6or 0.75 of the 28 day strength and the post-tensioning is slightly higher than what was

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assumed in the analysis for final effective forces since long term losses have not taken place.Often it is assumed that there is no live loading.

FIGURE 1.10.2-1

The results of the Initial Analysis can be included on the Results Report by checking theappropriate box on the Report Setup screen. The that are files generated by the analysis canalso be viewed in a wordprocessor. The files are as follows:

INITIAL.DAT Input listing and additional required mild reinforcement due to initial stresses.

INISTL.DAT Total mild reinforcement (non-prestressed) required due to initial stresses.

INISTRS.DAT Distribution of initial stresses at 1/20th points along each span.

1.10.3 Lateral Analysis

The Lateral Analysis option allows the user to determine if additional mild steel is required forlateral moments. The information required for Lateral Analysis is entered via the Post-Processors item on the Action menu. Figure 1.10.3-1 shows the tab for Lateral AnalysisSettings, the lateral moments are entered on the second tab. The load combinations shownare typical combinations for design, however they may vary depending on the governingcode.

The user can specify what percentage of the post-tensioning available in the frame should beconsidered as contributing to lateral moment resistance. For two-way systems, the user mustalso specify either the number of strands or the percentage of post-tensioning which is avail-able for transfer of column moments.

Note that the steel shown for the Lateral Analysis may be less than that required for eitherminimum code requirement or the ultimate moment combination. The user must check todetermine what requirement governs. Data block 11 of the Results Report shows the steelrequired for code minimums and ultimate moment.

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FIGURE 1.10.3-1

The results of the Lateral Analysis can be included on the Results Report by checking theappropriate box on the Report Setup screen. The files that are generated by the analysis canalso be viewed in a wordprocessor. The files are as follows:

LATERAL.DAT Summary of critical analysis and design information including totalmild steel required for lateral moments.

LATBM.DAT The factors used for moment combinations and the moments at 1/20th points along each span.

LATERAL.DAT Mild reinforcement requirements of the critical lateral and gravitymoment combination.

1.10.4 Stresses

The Stresses post-processor allows the user to graphically display the stresses resulting fromdifferent load combinations. The load combination data is entered via the Post-processorsoption on the Action menu. The load combinations can be set as any fraction of the live load,dead load and post-tensioned load.

Note that the Stresses post-processor is intended as a serviceability check in addition to theService Load Combination used for the analysis. The Stresses Results graph is the only placethat these changes are shown. The results of the analysis as shown on the Results Report arenot changed and there is no recalculation of the moments or required reinforcement. Theresults of the Stresses post-processor can be viewed on the Stresses Results Graph by

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selecting the ‘User Combination’ option. Figure 1.10.4-1 shows a Stresses Results Graphfor the User Combination option.

FIGURE 1.10.4-1

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ADAPT PROGRAM EXECUTION

LIST OF CONTENTS

2.0 GENERAL .............................................................................................................. 2-1

2.1 OVERVIEW ............................................................................................................ 2-1

2.2 THE MAIN PROGRAM WINDOW .......................................................................... 2-22.2.1 MENU ITEMS AND CORRESPONDING MAIN TOOLBAR BUTTONS: ......... 2-3

File Menu ..................................................................................................... 2-3Action Menu ................................................................................................. 2-3View Menu ................................................................................................... 2-3Options Menu .............................................................................................. 2-4Window Menu ............................................................................................... 2-5Help Menu .................................................................................................... 2-5

2.3 INPUT EDITOR ...................................................................................................... 2-52.3.1 INPUT SCREENS ........................................................................................ 2-6

A. PROJECT INFORMATION ................................................................. 2-8B. GEOMETRY ...................................................................................... 2-9C. LOADING (Fig. 2.3.1-13) ................................................................ 2-15D. MATERIALS .................................................................................... 2-17E. CRITERIA ........................................................................................ 2-19

2.3.2 SAVING INPUT DATA................................................................................. 2-232.3.3 DATA ENTRY FOR A NON-PRISMATIC SECTION ..................................... 2-252.3.4 STAND-ALONE DATA ENTRY ................................................................... 2-262.3.5 CONVERTING UNITS................................................................................. 2-272.3.6 FEATURES SPECIFIC TO THE BRITISH CODE ........................................ 2-272.3.7 FEATURES SPECIFIC TO THE CANADIAN CODE................................... 2-27

2.4 GRAPHICAL DISPLAY OF INPUT GEOMETRY ................................................. 2-282.4.1 VIEWING CAPABILITIES ............................................................................ 2-292.4.2 DESCRIPTION OF VIEWER OPERATION ................................................. 2-30

2.5 PROGRAM EXECUTION ....................................................................................... 2-322.5.1 RECYCLE WINDOW TABS ....................................................................... 2-332.5.2 DESIGN INDICATOR BOX ......................................................................... 2-372.5.3 RECYCLE WINDOW CONTROL BUTTONS .............................................. 2-382.5.4 USER INTERACTION ................................................................................. 2-40

2.6 VIEWING AND PRINTING OUTPUT ................................................................... 2-442.6.1 RESULTS REPORT SETUP ...................................................................... 2-442.6.2 REPORT HEADING ................................................................................... 2-452.6.3 VIEWING AND PRINTING THE RESULTS REPORT .................................. 2-462.6.4 VIEWING AND PRINTING RESULTS GRAPHS .......................................... 2-462.6.5 PRINTER SETUP ....................................................................................... 2-47

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ADAPT PROGRAM EXECUTION

2.7 PRINCIPAL OUTPUT FILES ............................................................................... 2-48

2.8 SAVING PROJECTS ........................................................................................... 2-49

2.9 TENDON SELECTION MODE............................................................................. 2-512.9.1 OVERVIEW ................................................................................................ 2-512.9.2 DESCRIPTION OF FEATURES ................................................................. 2-51

Tendon types .............................................................................................. 2-51Stress Loss Calculations ............................................................................ 2-54

2.9.3 DATA INPUT FOR LONG-TERM STRESS LOSS CALCULATIONS ........... 2-542.9.4 DESCRIPTION OF EXECUTION ................................................................ 2-552.9.5 DIFFERENCES IN LONG TERM STRESS LOSS COMPUTATIONS.......... 2-57

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ADAPT PROGRAM EXECUTION Chapter 2

2.0 GENERAL

This chapter describes the data input, program execution and procedures for saving and recallingdata. It also discusses options for viewing and printing the output and execution of the post-proces-sors. It is written for the individuals who are going to be using the ADAPT Post-tensioning software.It assumes that ADAPT-PT is already installed on the computer and that the user is editing or gener-ating data for new runs. It also assumes that the user knows the features and the scope of the pro-gram, such as the type of sections, loading and design criteria. This information is covered in Chapter1 of this booklet.

The user in doubt about the theoretical background or underlying assumptions of ADAPT is urged toreview Chapter 4 of the Software Manual. An understanding of the theory and assumptions helpsensure that the structure is being modeled appropriately and within the limits of the software.

New users are encouraged to run one of the examples included with the program. There are ex-amples for all of the different codes in American (ft-lb), metric and MKS units. The different versionsof example MNL5-2 are shown in the table below. MNL5-2 is a three span two-way slab with dropcaps. Printouts of examples MNL5-2 and MNL5-2M are included in Chapter 5 of the Softwaremanual. There are additional examples in Chapter 6 of the Software Manual.

Code Units Example ACI American

SI MKS

MNL5-2 MNL5-2M MNL5-2K

British SI MNL5-2B Canadian SI MNL5-2C

2.1 OVERVIEW

A full cycle for the analysis and design of a post-tensioned structural member using ADAPTconsists of:

• Structural modeling;• Data entry;• Execution of the analysis; and,• Optional post-processing.

During the structural modeling step, the user defines the basic analysis and design parameters,i.e. the structural system (beam, one-way or two-way slab), the span lengths, cross-sectionalgeometries, tributary widths and supports. The user also defines the loading, allowablestresses and reinforcement covers. This is the most critical stage of the design process. Theuser’s experience and engineering judgment play a major role in the selection of suitabledesign parameters. This stage of the design should be performed, or at least reviewed, by asenior engineer. A structure which is not modeled correctly is not likely to yield reasonableresults using ADAPT or any other software.

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Data entry in ADAPT is independent from the execution of the analysis. Data for a particularproject may be entered at any time for later execution. Data is entered through a spread-sheet-like Input Editor described in Section 2.3. A 3-D graphical viewer, described inSection 2.4, allows the model to be viewed on the screen and/or printed.

The program may be executed in either automatic or interactive mode. In the automaticmode, the program attempts to come up with a design that meets all of the user specifiedrequirements without any user intervention. The program performs similar calculations in theinteractive mode but the user has the opportunity to optimize the design through adjustmentsin the post-tensioning forces and drapes. In most cases, it is more appropriate to use theinteractive mode.

After completion of the calculations the results may be viewed on the screen and/or printed.Output options include graphs, a detailed Results Report and a graphical Summary Report.Optional post-processors allow the user to do calculations for Initial Stresses, Lateral Analy-sis, Prestress Losses and additional Load Combinations.

2.2 THE MAIN PROGRAM WINDOW

Figure 2.2-1 shows the main ADAPT-PT program window as it appears once a project hasbeen opened. All program functions including data entry, program execution and post-processing are accessed through the Main Program window. Menu options will be grayedout when they are not applicable. For example, if there is no project open, the ‘Save As’,‘Close’ and ‘Print’ options on the File Menu will be grayed out.

FIGURE 2.2-1

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2.2.1 Menu Items and Corresponding Main Toolbar Buttons:

File Menu

New Starts a new project.

Open Opens an existing project.

Save As Saves both the input files and the Results report file under auser-specified filename.

Close Closes the currently open project

Delete IntermediateFiles Deletes all intermediate calculation files from the current

project directory

Export Graph Allows the user to export the currently active graph aseither a bitmap (.BMP) or a Windows metafile (.WMF).

Print Prints the currently active report or graph window.

Print/Page Setup Sets the paper size, report margins and paper orientation.

Exit Closes all windows and exits the program.

Action Menu

Enter/Edit Data .

Opens the data input editor.

Execute Analysis Executes the program calculations.

Recycle Window Opens the recycling window. Used when re-running aproject in order to adjust the post-tensioning force orprofile.

Post-Processors Opens the dialogue box for selecting and running the post-processors.

View Menu

Status Bar Turns the status bar at the bottom of the main window onand off.

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Results Report Opens a window for viewing the Results Report.

Graphs The Graphs menu item opens a submenu which allows anyor all of the Results Graphs to be viewed. The ShowGraphs button on the main toolbar displays all graphs.

PT Summary Creates and displays a one-page graphical summary report.

Viewer Starts the 3-D graphical viewer.

Options Menu

Default Code Allows the user to select the default code (ACI, Canadian,British).

Default Units Allows the user to select the default units (American, SI,MKS).

Auto-Execution ofPost-Processors If this option is checked the calculation is done automati-

cally.

Remember PrinterSelection If this option is checked, the program uses the latest printer

settings for all future runs, regardless of the default printerselected in the Windows settings.

Report Heading Opens a dialogue box which allows the report header to beedited.

Report Setup Opens a dialogue box where the report contents may beset. This includes the option to append detailed 1/20thpoint data to the report.

Report Font... Opens a dialogue box where the Report font may be sent.For best results the font should be set to Courier New.

Graph Properties Configures the graphs generated by the program. Optionsinclude whether to include X and Y gridlines, min/max datapoints and a legend.

Spreadsheet Options Configures the action of the ENTER key in the data entryspreadsheets. The key may be set to move the cursor right,down or stay in the same field.

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Window Menu

This menu lists which of the graph windows are open and indicates whether the ResultsReport window is open. The graphs may be stacked vertically for scrolling or thewindows may be cascaded.

Help Menu

Contents Shows the help contents of ADAPT-PT.

Calculator Invokes the standard Windows calculator.

System Information Lists the System hardware & software configuration.

Local Key Status Indicates status of the local protection Key.

Network Key Status Provides tools to operate the program using a network Key

Key Troubleshooting Provides information on troubleshooting problems with theKey

About ADAPT Company address, phone, fax and e-mail information

About ADAPT-PT Program information

Technical Support Information on how to obtain technical support

Disclaimer Defines responsibility of the software user.

2.3 INPUT EDITOR

The input editor is used both to enter new projects and edit existing files.

• To start a new project either click New on the File Menu or click the New button on the Main Toolbar.

• To edit an existing Version 6 ADAPT file, either select the Open item on the Filemenu or the Open button on the Main Toolbar. This will bring up a list of the.ADB files in the default data directory. After selecting the desired file, click oneither the Enter/Edit Data item on the Action Menu or the Enter/Edit Data button

.

• To edit a Version 5.x ADAPT file, click on the arrow next to the ‘Files of type:’box and select [Old-ADAPT (*.PT)].

Note: To open a version 5.x file all of the associated input files (*.PT, *.CLD, *.CCR,*.CGE) must be in the same directory.

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FIGURE 2.3-1

2.3.1 INPUT SCREENS

Data is entered and displayed via a series of input screens. The screens are arranged as follows:

A. Project Information;B. Geometry;C. Loading;D. Material; and,E. Design Criteria.

When first entering data for a project, the user would typically go through the screens in order byclicking on the Next and Back buttons or pressing ALT-N and ALT-B. In subsequent editing,specific screens may be selected from the menus.

Much of the information on the Material and Design Criteria screens will be the same from project toproject. Experienced users will find that on a typical project it may only be necessary to enter theProject Information, Geometry and Loading.

The three-span frame shown in Figs. 2.3.1-1 through 2.3.1-3 will be used to explain the data inputprocess. Please note that this example is only intended to illustrate the ADAPT data input features.It is not intended to represent an economical, or even a realistic, design.

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FIGURE 2.3.1-2

FIGURE 2.3.1-1

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The data entry screens are as follows:

A. PROJECT INFORMATION

General Settings (Fig. 2.3.1-4)

FIGURE 2.3.1-4

The General Settings window automatically opens when a new project is started or anexisting project is opened. The General title of the project will appear at the top of the firstpage of output. The Specific title will appear at the top of each subsequent page of output.

FIGURE 2.3.1-3

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FIGURE 2.3.1-5

For two-way slab systems, the user has the option of modeling the structure using the Equiva-lent Frame Method (EFM). For one-way systems, and two-way systems where EquivalentFrame Method is not used, there is an option to increase the moment of inertia over thesupports. Both of these options affect the relative stiffness of the beam and column members.This, in turn, affects the relative distribution of the moments and may affect the amount ofpost-tensioning required. For more information on modeling options, see Chapter 4 of theSoftware Manual.

B. GEOMETRY

The geometry of the problem is defined via a series of input screens that can be accessedfrom the Geometry menu. The screens will vary slightly depending on which structural systemhas been specified. There are three basic screens: Span Geometry, Supports – Geometry,and Supports – Boundary Conditions. Additional screens are used to enter effective flangewidths, segmental data, drop caps, drop panels and transverse beams. The screens are asfollows:

If the structural system is specified as a two-way slab, the user is given the option of includingdrop caps, transverse beams and/or drop panels. If the structural system is specified as abeam, the user is given the option of considering an effective flange width in the calculations.Typically the answer to this would be ‘Yes’.

Segmental Input is used for entering non-prismatic structures, i.e. those where the tributarywidth or the depth of the section changes within a span. Most structures can be entered withConventional Input however. With Conventional Input the tributary width, section type and/or the section depth can vary from span to span; Segmental Input is only necessary if theyvary within a span.

Design Settings (Fig. 2.3.1-5)

The Design Settings screen is used to select various calculation and design options. Theselection of Automatic versus Interactive mode is discussed in Section 2.5. The other optionsinclude whether to reduce the moments to the face of the supports and whether to allowlimited plastification (moment redistribution).

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Span Geometry (Fig. 2.3.1-6)

The Span Geometry screen is used to enter the cross-sectional geometry of the slab or beamat midspan. To set the number of spans, use CTRL+/- or click on the up/down arrow at theleft of the screen.

The dimensions that need to be entered (b, h, etc) will depend on the section type. Alldimensions are defined in the legend at the top of the screen and/or illustrated in the appropri-ate section figure. The section type for any span can be changed by clicking on the button inthe Section (Sec.) column.

FIGURE 2.3.1-6

The reference height (Rh) identifies the position of a reference line that is used in determininghow to display tendon heights. The reference height indicates the distance from the referenceline to the top of the slab with positive being measured upwards. Typically, the referenceheight is set equal to the slab depth. The soffit of the slab/beam is thus used as the referenceline.

Tendon heights are shown with respect to the reference line. Using the bottom of the slab asthe reference line thus shows tendon heights as height above the slab soffit. This is how theyare shown on most structural drawings.

Figure 2.3.1-7 shows several different reference height configurations. Typically the samereference height is used for all spans. The reference height can thus be set via the typical row.If the slab or beam depth changes, the same reference height can still be used as long as theresulting tendon heights are adjusted accordingly when transferred to the structural drawings.Alternatively, the reference height can be entered as zero which will set the reference line atthe top of the slab. If the reference line is at the top of the slab, tendon heights will be shownas negative numbers, indicating distance below the top of the slab.

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FIGURE 2.3.1-7

The reference height can be changed from span to span to model steps at the top of the slab.If this is done however, it will be necessary to adjust the tendon profiles so they match at the

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supports. In general, it is best to use the same reference height for all spans. Changes in theslab depth should be modeled accurately however to ensure that the calculations are donecorrectly.

The left and right multiplier columns (<-M and M->) are used to specify the tributary width.Tributary widths can be specified using either the Unit Strip method or the Tributary method.This is discussed in more detail in Section 1.4.2.

The typical input row (top row) can be used if several spans have similar dimensions. Toenter typical values, type the value into the appropriate cell in the top row and then pressENTER. The typical value will be copied to all spans.

Unit strips, for example, are typically entered with a width of 12 in. (or 1000 mm). Typing 12(or 1000) into the ‘b’ column in this row and pressing ENTER will cause all spans to beassigned a width of 12 in. (or 1000 mm). The value of any field initialized in this manner canbe subsequently changed as necessary. Data can be entered in the typical row at random; itis not necessary to enter values in all fields of the typical row.

If there are cantilevers on the right and/or left ends of the frame, they are added by clickingon the appropriate check box. This will activate the input fields for the corresponding cantile-ver.

If any of the spans need to be entered as non-prismatic, the Segmental option on the GeneralSettings screen must be selected. Section 2.3.3 discusses entry of non-prismatic sections inmore detail.

Effective Flange Width (Fig. 2.3.1-8)

If you are entering a beam and you answered ‘Yes’ to ‘Consider Effective Flange Width’ onthe General Settings screen, the Span Geometry screen will be followed by the EffectiveFlange screen. If you choose to use the ACI method of effective flange width calculation, theresulting flange widths will be displayed but you will not be able to edit them. If you select‘User Input’ calculation, the effective width column (b

e) will default to the ACI calculated

values but you will be able to change them.

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FIGURE 2.3.1-8

Note that ACI does not actually specify an effective flange width for prestressed beams. Thewidths calculated by the program are in accordance with the ACI recommendations fornonprestressed beams.

Supports - Geometry (Fig. 2.3.1-9)

This screen is used to input column heights, widths and depths. You may enter dimensions forcolumns above and below the slab, above only, or below only. If you are entering a one-wayslab, you would enter data for walls. The ‘No Walls’ option would be selected for a slabsupported on beams.

Units and dimensions are as shown on the figures. H1 is the distance from the mid-depth ofthe slab to the top of the slab below. H2 is the distance from the mid-depth of the slab to thebottom of the slab above. For a rectangular column, the “D” dimension is the dimension inthe direction of the frame. For a circular column, the diameter is entered in the Dc column.

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FIGURE 2.3.1-9

Supports - Boundary Conditions (Fig. 2.3.1-10)

This screen is used to enter support widths and column boundary conditions. For columns,the typical boundary condition is fixed at both ends of the columns above and below the slab.A different boundary condition may be assigned to each of the four ends however.

Support widths are only entered if you answered ‘Yes’ to the ‘Reduce Moments to face-of -support’ question on the Design Settings screen. To set the support width to the columndimension (D), check the “SW = Column Dimension” box.

If ‘No Columns’ was specified on the Supports-Geometry screen the boundary conditionentries will be ignored. The support widths will be used to calculate reduced moments,however.

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FIGURE 2.3.1-10

Geometry - Drop Cap/Transverse Beam (Fig. 2.3.1-11)

To enter drop caps or transverse beams for two way slabs, you must answer ‘Yes’ to the‘Include Drops & Transverse Beams’ question on the General Settings screen. Figure2.3.1-11 shows the screen for entering drop caps and transverse beams. The input param-eters are defined in the figures at the top of the screen. Note that H, the depth of the cap orbeam, is the total depth of the section, not the depth below the slab.

If there are drop caps or transverse beams with the same dimensions at several supports,their dimensions may be entered using the typical row. To enter typical values for drop caps,type the value into the typical row and press ENTER. The value will be copied to anysupports that have been marked as having drop caps. Any supports which are subsequentlymarked as having drop caps will also be assigned this value as a default.

Transverse Beams dimensions are entered in the same manner.

Geometry - Drop Panel (Fig. 2.3.1-12)

To enter drop panels you must answer ‘Yes’ to the ‘Include Drops & Transverse Beams’question on the General Settings screen. Drop panels are input the same way as drop caps.Typical values can be entered via the typical row at the top of the table.

C. LOADING (Fig. 2.3.1-13)

Figure 2.3.1-13 shows the screen used to enter loading information. Any number of differ-ent loads and load types may be entered for a span. You may also specify whether to skipthe live loading and whether to calculate selfweight automatically. If these features are se-lected, the skip factor and concrete unit weight must be entered.

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FIGURE 2.3.1-11

FIGURE 2.3.1-12

Loads may be entered for multiple spans by entering the span numbers separated by acomma (i.e. 1,5,6). If a load occurs on a series of consecutive spans it may be entered byspecifying the first span, a dash and the last span (i.e. 1-3). To enter a load for all spans enter‘all’ or ‘ALL’ as the span number. To enter loads on a left cantilever, enter either LC or 0 asthe span number. To enter loads on a right cantilever, enter either RC or the number ofspans+1 as the span number.

There are five load types: Uniform, Partial uniform, Concentrated, Line and Moment. Theload type may be specified by either typing U,P,C,L or M in the L-? column or by draggingthe icon from the top of the screen to the cell in the L-? column. The schematics for eachload type indicate the required input data. For information on the difference between lineloads and uniform or partial uniform loads, see Section 1.5.2. Each load must be specified aseither Dead Load (DL) or Live Load (LL).

Note that on cantilevers, distances are always measured from the support (Fig. 2.3.1-14).The distances for a left cantilever as thus entered contrary to those of the typical spans.

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FIGURE 2.3.1-13

FIGURE 2.3.1-14

D. MATERIALS

Material - Concrete (Fig. 2.3.1-15)

This screen is used to enter concrete properties. Depending on the code, the concrete weightclassification is used in shear and/or flexure calculations. Default values of the modulus of

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elasticity are calculated based on the concrete strength and the appropriate code formula.The ultimate creep coefficient is used in the calculation of long-term deflections.

FIGURE 2.3.1-15

Material - Reinforcement (Fig. 2.3.1-16)

FIGURE 2.3.1-16

This screen is used to specify reinforcement bar sizes and properties. When entering data fora beam, there will be an additional entry for Yield strength of the shear reinforcement. Thepreferred bar sizes are used when calculating the number of bars required. The bar sizesmay be changed on the PT Summary report, however.

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Material - Post-Tensioning (Fig. 2.3.1-17)

FIGURE 2.3.1-17

This screen is used to input the post-tensioning system parameters. The information enteredhere is used to calculate the Ultimate Moment capacity of the member when the “effectiveforce” option of the program is used. When “tendon selection” option is used, the effectivestress is calculated by the program. The stress in the tendon at nominal strength (fps) iscalculated from the effective stress and the reinforcement ratio.

E. CRITERIA

The screens for design criteria input are as follows:

Criteria - Allowable Stresses (Fig. 2.3.1-18)

FIGURE 2.3.1-18

This screen is used to enter initial and final allowable stresses. Tension stresses are input as amultiple of the square root of f’c, compression stresses are entered as a multiple of f’

c. The

values entered for final allowable stresses will be shown on the Stresses Compression andTension tab of the Recycle window.

Criteria - Recommended Post-Tensioning Values (Fig. 2.3.1-19)

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This screen allows the user to specify minimum and maximum values for averageprecompression (P/A; total prestressing divided by gross cross-sectional area) and percent-age of dead load to balance (Wbal). These values are used by the program to determine thepost-tensioning requirements shown on the Tendon Forces and Heights tab of the Recyclewindow. They are also used to determine the status of the Pmin/Pmax and WBAL Min/ Maxindicators on the Recycle window.

If data is being entered for a beam, the bottom section of the screen will ask whether toinclude the (DL + 25% LL) loading case. This is a UBC (Uniform Building Code) require-ment used to determine the amount of mild steel reinforcement required. If this is answered‘Yes’, the ratio of reduced live load to actual live load must be entered. This option allows areduced live load to be used for the post-tensioning if so desired but provides the full live loadfor the 25% UBC design loading. Live load reduction is optional; if the live load entered onthe Loading screen was not reduced, the ratio of reduced to actual live load would be 1.

FIGURE 2.3.1-19

If data is being entered for a one- or two-way slab, the bottom of the screen will ask for themaximum spacing between tendons. This is entered as a multiple of the slab thickness (i.e. 8x thickness). The program does not check tendon spacing however, this is something thatmust be checked on the shop drawings. Tendon spacing is typically more of an issue fordetailing than design but on very thin, very lightly loaded slabs, it might control the design.

Note that the (DL +25%LL) provisionis not required by ACI-38, nor is it included in theIBC-2000 (International Building Code).

Criteria – Calculation Options (Fig. 2.3.1-20)

This screen is used to select the post-tensioning design option. The two options are ForceSelection and Force/Tendon Selection. Force Selection is the default option, in order to useTendon Selection, the Force Selection/Tendon Selection option must be specified. TendonSelection is discussed is Section 2.9.

If Force /Tendon Selection is specified, the screen will prompt for the information required tocalculate the prestress losses. The values given as defaults are fairly typical in the industryand should be used unless more accurate information is available. Long-term losses mayeither be entered as a lump sum value or the information required to calculate them may beentered.

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FIGURE 2.3.1-20

This same information is used for the Friction and Long-Term Loss post-processor calcula-tions. For more information on these calculations, see the chapter on Friction and Long TermLosses in the Software Manual.

Criteria - Tendon Profile (Fig. 2.3.1-21)

This screen allows the user to specify the tendon profiles. The profile and values shown, areversed parabola with the low point at mid-span and inflection points at span length/10, arethe defaults. These are typical industry defaults; they will be appropriate for most designswith essentially uniform loading.

The parameters used to define the tendon profiles are discussed in Section 1.6.3 and areshown in the schematics at the top of the screen. Note that if a non-standard profile, i.e. alow point at somewhere other than midspan, is used, this must be clearly called out on thestructural drawings. Transfer girders and slabs with heavy concentrated loads may require aharped profile. The low point is usually specified to coincide with the column being trans-ferred or the concentrated load.

Criteria - Minimum Covers (Fig. 2.3.1-22)

This screen is used to specify minimum covers for both the post-tensioning tendons and mildsteel reinforcement. Note that the cover for the pre-stressing steel is specified to the centerof gravity of the strand (cgs) whereas for mild steel it is clear cover. (For ½ in. strand, theclear cover on the tendon will be ¼ in. less than the distance to the cgs.)

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FIGURE 2.3.1-21

FIGURE 2.3.1-22

Criteria - Minimum Bar Length (Fig. 2.3.1-23)

FIGURE 2.3.1-23

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This screen is used to specify how mild steel reinforcement bar lengths are calculated. Thevalues entered for cut-off lengths are used to calculate top and bottom bar lengths whenminimum reinforcement requirements govern. The lengths of bars required for ultimatestrength are calculated from the reinforcement necessary to supplement post-tensioning at 1/20th points along each span. Bar lengths for both minimum steel and steel required forultimate strength will include the specified extension lengths.

Load Combinations (Fig. 2.3.1-24)

This screen is used to input the load combination factors for service and strength (ultimate)ultimate load conditions. It is also used to enter any applicable material factors. The defaultvalues will depend on which design code is being used.

FIGURE 2.3.1-24

Criteria - Design Code (Figure 2.3.1-25)

This screen allows the user to choose the design code. Depending on the code chosen,materials factors and other design parameters may need to be entered. These are entered onthe Load Combinations screen.

2.3.2 SAVING INPUT DATA

The input files generated for each project are as follows: *.adb, *.ccr, *.cge, *.cld, *.pt,*.tbx, where * is the filename you specify for the input data.

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FIGURE 2.3.1-25

To save the input data and execute the analysis, either select Execute from the Input Editormenu or click on the Save & Execute Analysis button . If you are entering a new project,you will be prompted for a file name and directory in which to save the file. Once the file issaved, the program will automatically execute the analysis. If you opened an existing project,it will be saved to the same directory, under the same filename. The program will thenautomatically execute the analysis. Figure 2.3.2-1 shows the dialog box for saving files.

FIGURE 2.3.2-1

To save the input data and return to the Main Program window, select either Save or SaveAs from the Input Editor File menu or select the Save button on the Input Editor Toolbar.If you have opened an existing file, Save will save the file under the same name, in the samedirectory. Save As will allow you to change the file name and/or directory. Once the file issaved, select Exit to return to the Main Program window.

Note that it is often not necessary to go through all of the screens, even when entering a newproject. Much of the information on the Materials and Criteria input screens will be the sameon many projects. The program is set up with defaults on all of these screens. If you want touse these defaults you can exit the Input Editor once you have entered the Project, Geometryand Loading information and made any changes to the defaults that are necessary.

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2.3.3 Data Entry for a Non-prismatic Section

The following example illustrates data entry for a non-prismatic section using the segmentaloption. The example is a single span beam which is made up of seven segments of varyingcross-sectional geometries (Fig. 2.3.3-1). Although this is not a practical design, it illustratesADAPT’s ability to model complex geometries. The segmental option is activated byselecting the Segmental item on the Design Settings screen. General span data is entered as ifthe beam were prismatic, except that for each span which requires segmental input, thePrismatic column is changed to ‘NP’ (Non-Prismatic).

FIGURE 2.3.3-1

Figure 2.3.3-2 shows the Span Geometry screen for this beam. Changing a span to ‘NP’activates the More… button in the Segments column. Clicking on the More… button opensthe Geometry-Span (More) window for that span.

FIGURE 2.3.3-2

The segment cross-sections are shown in Fig. 2.3.3-3. The screen used to enter the seg-ments in shown in Fig. 2.3.3-4.

Up to seven segments may be entered per span. The parameters are input in the samemanner as general span geometry data except the XL column is used to specify the distance

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from the left support centerline to the start of the segment. The length of each segment iscalculated automatically based on the distance to the start of the next segment. The start ofthe first segment is always zero.

Note that if either the ‘Equivalent Frame’ or ‘Increase moment of inertia over support’ optionwas selected, the program will automatically generate additional segments over each supportusing the geometry entered for the first and last segments. If these segments are generatedbefore the support dimensions are entered, their XL values will be initialized with values ofzero and the span length, respectively. These values will be updated when the supportdimensions are entered.

FIGURE 2.3.3-3

2.3.4 Stand-Alone Data Entry

Data entry can be done as a stand-alone function. The Hardware Key is not required. Afterthe input files are saved, either they will need to be transferred to a computer which has theHardware Key, or a Hardware Key must be attached to the computer to execute the analy-sis.

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FIGURE 2.3.3-4

When attempting to enter data on a computer which does not have the Hardware Key, youwill get a message telling you that you can enter data and view results of previous runs butyou cannot execute an analysis.

2.3.5 Converting Units

The default code and units are set via the Options Menu on the Main Program Window. Ifthe design is being done according to the ACI code, either American (ft-lbs), SI or MKSunits can be used. To convert between different systems of units, select the ‘Convert Units’item on the Input Editor Project Menu.

Note that if the design is being done according to either the British or Canadian code, only SIunits can be used. The ‘Convert Units’ option will not appear on the Project Menu unlessACI is being used.

2.3.6 Features Specific To The British Code

The British code allows slabs to be designed as either beams or slabs for shear. To design aslab as a beam, the structural system must be specified as a beam on the Design Settingsscreen. The British code also uses material factors rather than strength reduction factors inultimate strength calculations. This information is entered on the Load Combinations screen.Figure 2.3.6-1 shows the Load Combinations screen for the British code with the defaultmaterial factors.

2.3.7 Features Specific To The Canadian Code

The Canadian code uses material factors rather than strength reduction factors in ultimatestrength calculations. This information is entered on the Load Combination screen. Figure2.3.7-1 shows the default material factors for the Canadian code.

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FIGURE 2.3.6-1

FIGURE 2.3.7-1

2.4 GRAPHICAL DISPLAY OF INPUT GEOMETRY

While in the Input Editor, a three dimensional model of the structure can be displayed by eitherselecting the Viewer item on the Input Menu or clicking on the Viewer button . The Viewer can

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also be accessed from the Main Program window by clicking on the Viewer button or selecting theViewer item on the View Menu.

The Viewer allows perspective displays, zooming, panning and printing; the model can either bedisplayed as a wire frame or as solid surfaces.

2.4.1 Viewing Capabilities

Figure 2.4.1-1 shows plan and elevation views of a three-span, two-way slab frame whichhas been isolated from the rest of the floor system for analysis and design. As shown, thesecond column has a drop cap and a panel. The third span has a beam in direction of theframe. At the fourth support there is a beam perpendicular to direction of frame. Note alsothat there is a cutout in the slab in span three and the slab changes thickness from span two tospan three.

FIGURE 2.4.1-1

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2.4.2 Description of Viewer Operation

The viewing screen is shown in Fig. 2.4.1-2. You can view the model from any angle andzoom in and out using the mouse and the buttons on the toolbar, or the menu items whichappear if you right click the mouse. The following are several of the view options:

To Rotate the Model: Use action buttons for all four rotation directions or rotation mode button (Ro-

tate).

Figure 2.4.1-1 is drawn using CAD, not ADAPT. Figure 2.4.1-2 is a wireframe modelgenerated from the user’s input data using the ADAPT Viewer. In the ADAPT generatedviews, the lines perpendicular to the direction of frame delineate the different segments ofeach span. Each segment is a slice whose cross-sectional geometry may be different from theadjacent segments. Segments, therefore, represent changes in cross-section that would occurin nonprismatic frames.

If either the ‘Equivalent Frame’ or ‘Increase moment of inertia over support’ option wasselected, the regions over the supports are considered as additional segments. Figure 2.4.1-2 is a view of the model with solid surfaces.

FIGURE 2.4.1-2

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To Move the model:Use action buttons for all directions or use the Pan button (Pan).

To Zoom: Use zoom in/zoom out action buttons or zoom mode button (Zoom).

To View the Model: Choose one of the eight action buttons of different view directions.

To Print the Current View:Click on the Print button. To get the best quality printout, maximize the screenand zoom in on the model as much as possible before printing.

To Record and Play the View Motions:Use the motion record and play menu.

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2.5 PROGRAM EXECUTION

The program can be executed either by selecting the Execute Analysis item on the Action menu orclicking the Execute Analysis button on the Main Toolbar.

The program begins by reading the data files and performing a number of preliminary data checks. Ifan error is detected, the program will stop and display a message box indicating the most likelysource of the error. The data consistency checks are not exhaustive however; the user is ultimatelyresponsible for ensuring that the data is input correctly.

Automatic modeThe tendon forces and drapes can either be calculated automatically or interactively. In the automaticmode, the program attempts to select a post-tensioning force and profile within the design boundsspecified by the user. If a solution is possible, the program will complete the calculations and returnto the Main Program window. The results can then be viewed and/or printed. If a satisfactorysolution is not possible, the program will display a message box which describes the problem and willswitch to the interactive mode. The user can then decide whether it is possible to override the originaldesign criteria and continue with the design.

The automatic mode begins by assuming the maximum drape for each span and determining theminimum force which satisfies the maximum allowable tensile stresses. The same force is used for allspans. The force is then adjusted to meet the following requirements as specified by the user:

• Minimum percentage of dead loading to balance for each span;• Minimum average precompression for each span; and,• Maximum spacing of tendons (applies only to slabs).

After these initial adjustments, each span is checked for compliance with the following:

Maximum percentage of dead loading to balance: if the balanced loading in any span exceeds themaximum percentage specified by the user, the program adjusts the tendon drape in that span in orderto lower the balanced loading. It then recalculates the balanced loading and the related moments.

Average precompression and compressive stresses: if either the average precompression or thecompressive stresses exceed the maximum permissible values the program will stop and display amessage box. It then switches to the Interactive mode and displays the Recycle window.

Interactive modeThe interactive mode gives the user an opportunity to optimize the design by adjusting the tendonforces and tendon drapes in each span. It can be executed using either the Force Selection or Force/Tendon Selection mode. The following is a description of the Force Selection mode. The Force/Tendon Selection mode is discussed in Section 2.9.

The program begins by going through the same calculations that it goes through for the Automaticmode. After it has determined an initial tendon force and profile however, it displays the Recyclewindow shown in Fig. 2.5.1-1.

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The Recycle window is comprised of five tabs which display information about the post-tensioningdesign, a Design Indicator box which summarizes the status of the current design, a Status indicatorand four control buttons: Recycle, Recall, Graphs and Exit.

2.5.1 Recycle Window Tabs

The Recycle Window tabs are as follows:

Tendon Forces & Heights Tab (Fig. 2.5.1-1):

This screen allows the user to adjust the tendon heights and post-tensioning forces. Thetable lists the post-tensioning forces at the midpoint of each span, the tendon heights atthe left, center and right of each span, the average precompression at midspan (P/A mid)and the percentage of dead loading balanced in each span (Wbal % DL).

Adjustments in tendon force, and/or tendon height may change the averageprecompression and the percentage of dead load balanced. These changes are re-flected in the P/A and Wbal columns as the changes are made. In order to see how thechanges affect the stresses and average precompression at locations other than midspan,however, it is necessary to recycle the window.

FIGURE 2.5.1-1

PT Forces Tab (Fig. 2.5.1-2):

The PT forces tab shows the PT forces provided in the left, center and right region ofeach span as well as the forces required in each region for minimum P/A. Thepost-tensioning force provided in each region is compared with the governing minimumforce in that region as shown on the Required Forces tab. If the provided force doesnot envelop the required values, FORCE NG (No Good) is displayed in the indicator

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Required Forces Tab (Fig. 2.5.1-3):

This tab shows the required post-tensioning forces for the most recently calculatedprofile. Note that all values in the tables are forces and that these forces refer to theentire tributary width entered in the geometry input.

The window consists of three sections. The left (light blue) boxes display the governingforces for the left, center and right region of each span. The force selected for eachregion is the largest required force based on tensile stresses in that region, minimum P/Aand minimum percentage of dead load to balance. The middle (light yellow) boxesdisplay the forces required for tensile stresses. If the moments in a particular region aresuch that no post-tensioning is required, a zero (0) is shown.

The first column of the right (light green) section is the post-tensioning force required tosatisfy the minimum average precompression specified by the user, based on themember’s cross-sectional area at midspan (P/A mid). Average precompression is basedsolely on the cross-sectional area; it is not a function of the applied loading or tendonprofile.

FIGURE 2.5.1-2

box at the top of the screen. Forces which are less than what is required will be high-lighted in red in the Provided PT Force columns.

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FIGURE 2.5.1-3

The second column of the right section (Wbal %DL) is the force required to provide anuplift equal to the minimum percentage of the total dead loading specified by the user.The force required for each span depends on the tendon geometry and loading of thatspan. All the dead loads, including superimposed dead load, are summed for each span,regardless of whether they are self weight, uniform or concentrated. The upward anddownward forces resulting from different tendon profile are illustrated in Fig. 2.5.4-1.Note that when calculating Wbal for display on this screen, the downward tendon forcesare not included. This approximation is made only for the purposes of obtaining a rapidscreen display. The actual computations of moments and stresses include all forces ineach tendon.

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Stresses Tension and Compression (Fig. 2.5.1-4):

FIGURE 2.5.1-4

This tab shows the maximum tensile and compressive stresses in the left, center and rightregions of each span. The stresses are calculated at 1/20th points and the highest stressin each region is displayed. If any of the stresses displayed are more than the allowablevalue, they will be highlighted in red. If the stress at any of the 1/20th points exceeds theallowable value, an NG warning is displayed in the indicator box. The location of thecritical stress values can be determined by looking at the Stresses Recycle graph.

Tensile stresses are shown as a ratio of the square root of the concrete compressivestrength at 28 days ( f’c

1/2). Compressive stresses are shown as a ratio of f’c. Theallowable stress values are shown for reference.

Tendon Selection and Extents Tab:

This screen is used to edit tendons when using the Force/ Tendon Selection mode. TheForce/Tendon Selection mode is discussed in Section 2.9.

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2.5.2 Design Indicator Box

FIGURE 2.5.2-1

The status of the current design is summarized and displayed in the Design Indicator box atthe top center of the Recycle window. Each design check is identified as either OK or NG(No Good).

The items displayed in the Design Indicator Box are as follows:

Cycle No: #Each time a force or tendon height is adjusted and recycled, the program recalculates therelated balanced loadings, moments, stresses, average precompression and percent ofdead load balanced. Each set of calculations is referred to as a cycle. The number ofcycles executed for a particular design is shown in the CYCLE block. In most cases twoto three cycles are adequate to arrive at an acceptable solution. It is rarely necessary toexceed five cycles.

WT ### Lb, or ### KgThe weight of post-tensioning strand required to provide the selected forces is estimatedand displayed in either pounds or kilograms.

The weight is estimated as follows: The force supplied by each strand is calculatedbased on its cross-sectional area and final effective stress, both of which are values inputduring data entry. The number of strands required to provide the forces shown on theTendon Forces and Heights tab is then determined. The actual length of each strand isassumed to be its calculated length plus 3 feet (1 meter) to allow for a stressing tail. Ifthe force changes between successive spans, it is assumed that the larger force extendsover the common support and the tendons are anchored at the fifth-point of the nextspan (see Fig. 2.5.4-2). If the forces are modified, the weight is recalculated anddisplayed after the window is recycled.

Force OKThis block indicates whether the selected post-tensioning forces meet all criteria at all 1/20th points along the member. The governing minimum forces for each span are dis-played in the left section of the Required Forces tab (Fig. 2.5.1-3). If the providedforce is less than the value required at any of the 1/20th points along the member, ForceNG will be displayed.

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Pmin OK Pmax OKThis block compares the average precompression at midspan with the minimum andmaximum values entered by the user. If the average precompression is above or belowthe specified limits, an NG is displayed.

Note that although the Force indicator considers the P/A all along the span, this blockonly considers the P/A at midspan. If the P/A is above or below the specified limits in asupport region, the PMIN and PMAX indicators will show OK however the Forceindicator will show NG.

In two-way slabs with drops or transverse beams for example, the cross-sectional areaat the supports will be much larger than the cross-section at midspan. Providing theminimum P/A at the supports may result in a much higher P/T force than necessary.Typically, the post-tensioning is adjusted so that the P/A at the supports is lower than thespecified minimums. The Force indicator will thus show NG even if the P/A at midspanis within the specified limits.

The PT Forces tab (Fig. 2.5.1-2) shows the post-tensioning force required in each ofthe three regions of each span.

Stresses Tens OK Comp NGThis block compares the tensile and compressive stresses with the allowable valuesspecified by the user. The maximum stresses in each span are shown on the StressesTension and Compression tab (Fig. 2.5.1-4).

Wbal Min-OK Max-NGThe total upward force of the tendon (Wbal) in each span is computed from thepost-tensioning force in span and the tendon geometry in the span. This upward force iscompared with the total dead loading on the respective span. An OK for both WbalMin and Wbal Max means that the ratio of balanced loading to the total dead loading fellwithin the limits specified by the user in all spans. The percentage of dead load balancedin each span is shown on the Tendon Forces & Heights tab (Fig. 2.5.1-1). The forcerequired to balance the specified minimum percentage of dead loading is shown on theRequired Forces tab (Fig. 2.5.1-3).

2.5.3 RECYCLE WINDOW CONTROL BUTTONS

Recycle

The Recycle button causes the stresses and required forces along the member to berecalculated based on the current tendon profile and forces.

If changes are made to either the tendon profile or force in any span, the status indicatorat the top right of the Recycle window will begin to flash. Once all of the changes are

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made, click on the Recycle button to update all of the tabs, the Design Indicator box andthe Recycle Graphs.

Recall

The Recall button allows the user to undo editing changes by recalling the tendon forcesand profile from the previous recycle. After selecting Recall, the window must recycledagain in order to update the tabs, the Design Indicator box and the graphs.

Graphs

The Graphs button displays a set of three graphs which provide detailed information onthe tendon profile, the tension and compression stresses and the required versus pro-vided post-tensioning forces. The Recycle graphs are shown in Fig. 2.5.3-1.

FIGURE 2.5.3-1

The graphs are as follows:

� Tendon Height: The Tendon Height graph can be used as a means of verifying thatthe tendon profile is at least reasonable. This graph allows the user to see the

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tendon profile either by itself or as it relates to the member elevation (concreteoutline). This can be helpful for finding input errors such as a tendon profile thatextends outside the member, or a profile that is not continuous. The concreteoutline shows all steps, drop caps/panels, transverse beams and changes in thick-ness.

� Stresses: This graph plots the maximum compressive and tensile stresses at the topand bottom face of the member. Dead, Live and Post-Tensioning loadings caneither be shown separately or combined. The Verify Allowable Stresses optionshows the combined stresses along with an envelope of the allowable stresses. Thegraph provides easy interpretation of stress results and clearly shows if stress limitsare exceeded.

� Post-tensioning: This graph shows the required and provided post-tensioning forceat 1/20th points along each span.

The graphs may be configured to show only certain spans and values by clicking on thecheck boxes at the left of the window. To maximize a graph for detailed viewing orchange the display options, right-click on the desired graph and use the editing menu thatopens up.

Exit

Selecting the Exit button closes the Recycle window. The program continues with thecalculations based on the most recent tendon force and profile selection. At the conclu-sion of the calculations, it returns to the Main Program window. The Results Report, thePT Summary Report and the Results Graphs may then be viewed and/or printed.

Note: if Force or Profile adjustments are made and the window is not recycled beforeexiting, the program will automatically do a Recycle.

2.5.4 USER INTERACTION

Tendon Forces & Heights may be edited on the Tendon Forces and Height tab (Fig. 2.5.1-1). When the program does the initial calculation for tendon forces, it assumes the sameforce for the entire frame, i.e. all tendons are full length. Tendon forces and heights may beadjusted in each span in order to arrive at an optimal post-tensioning design.

The user may choose different forces for different spans by using partial length tendons. Theeconomy achieved in using partial length tendons may be evaluated by viewing the weight ofstrand after the screen is recycled.

FORCE: The first column on the Tendon Forces and Heights screen shows the force at thecenter of each span. For the initial design, the algorithm uses the same force for all spans.The largest governing force is selected and the tendon is assumed to have its maximum

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permissible drape. Although this layout may work in some cases, it will typically not besatisfactory when span lengths, geometry and loading vary from one span to the next. Inparticular, the dead load will be overbalanced in short spans that are adjacent to long spans.

If the average precompression or percentage of dead load balanced in the initial calculationsdo not fall within the limits specified by the user, an NG will be displayed in the DesignIndicator box.

TENDON HEIGHTS: The second, third and fourth columns of the Tendon Force andHeights tab indicate the distance from a user selected reference line to the cgs (center ofgravity of strand) at the left, center and right of each span. The reference location is deter-mined from the reference height entered on the Span Geometry screen.

The choice of reference height has no effect on the calculations. It is important to know whatwas used as the reference height when transferring information to the structural drawingshowever. Usually, this will be obvious from what the program calculates as the tendonprofile. The tendon profile is shown on the Tendon Heights graph.

Fig. 2.3.1-7 shows several different reference height configurations. When the slab soffit isused as the reference line for adjacent spans which have the same depth, the tendon heightswill be equal at the common support. In this case, the tendon heights can be transferred tothe structural drawings as shown on Tendon Forces & Height screen and the Results Report.

When adjacent spans are different depth as in Fig. 2.3.1-7 (b), the tendon heights must beadjusted in those spans where the depth does not match the reference height.

As an example, a parking garage might have some bays with a 5-in. (160-mm) thick slab andsome bays with an 8-in. (200 mm) thick slab. If the reference height was set to 8 (200), thetendon heights as shown on the screen will be correct for the sections of 8-in. (200-mm)thick slab. In the bays with the 5-in. (160-mm) thick slab, the tendon heights shown on thescreen must be reduced by 3 inches (40-mm) when they are transferred to the structuraldrawings.

Note that the reference line can also be set to the top of the slab. In this case, the programwill show the tendon heights as negative numbers, indicating distance below the top of theslab. The reference height is discussed in more detail in Section 2.3.1.

ADJUSTMENTS: The force and tendon profile in any span can be edited independently.The upward and downward forces resulting from different tendon profile are illustrated in Fig.2.5.4-1. The P/A and Wbal figures on the right side of the screen will be updated each timea change is made. The Wbal figure is only an approximation however; it will not be com-pletely re-calculated until a Recycle is done. If an adjustment is made to either a force orprofile value, the Design Indicator checks will be blanked out and the Recycle message willstart to flash. Any number of adjustments can be made before doing a Recycle though.Selecting Recycle causes a complete recalculation of all stresses and updates all the DesignIndicator checks.

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FIGURE 2.5.4-1(adpt215-g)

CAUTION

The ability to edit tendon forces and profiles and immediately view the outcome of thechanges is a powerful tool for the skilled engineer. Less experienced engineers arestrongly encouraged to make sure their modifications are reasonable from a constructionpoint of view.

In particular, three considerations must be kept in mind:

1. As discussed in Section 1.4.2, a slab may be modeled either as a stripwhose width is equal to the tributary width or as a unit strip with theappropriate left and right multipliers. Both modeling schemes aretreated the same internally by the program and thus yield identicalsolutions. All forces shown on the Recycle window tabs are for the fulltributary width entered by the user.

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2. Each tendon must have at least one of its ends terminating at a free slab/beam edge (or an internal stressing pocket) to allow stressing. Notethat the program will not check to see if a post-tensioning layout isreasonable or even if it feasible.

3. The program assumes that a tendon terminated at any support actuallycontinues over the support and is anchored at the centroidal axis at spanlength/5 in the next span (Fig. 2.5.4-2). In both of the tendon arrange-ments shown in Fig. 2.5.4-2, the PT force is assumed to be 38 kips(170 kN) at either side of the interior supports. The balanced loadingof the structure is adjusted to include the portion of the tendon in thenext span. Both the contribution of the terminated tendon to the aver-age precompression over the support and the influence of this tendon onthe ultimate strength of the support region are accounted for by theprogram. To see the contribution of the added tendon, select theBalanced Loading item on the Detailed Output tab of the ResultsReport setup. The extent of the force may be seen on the Post-Tensioning section of the Recycle Graphs screen (Fig. 2.5.3-1).

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FIGURE 2.5.4-2

2.6 VIEWING AND PRINTING OUTPUT

2.6.1 Results Report Setup

The Results Report is comprised of independently selected data blocks. The data blocksmay be selected via either the Report Setup item on the Options Menu or the Report Setupbutton

on the Main Toolbar. This will bring up the window shown in Fig. 2.6.1-1.

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FIGURE 2.6.1-1

The Results Report generated with the blocks selected in Fig. 2.6.1-1 will contain the Gen-eral Input (data block 1), Selected Post-tensioning (data block 9), Factored Moments (datablock 10) and Rebar Required without Moment Redistribution (data blocks 11.1 to 11.4).

The data blocks are discussed in more detail in Section 1.9.1. The Basic Output tab lists theblocks that are customarily included in the Results Report. The items on the DetailedOutput (Fig. 2.6.1-2) are detailed listings of actions and results at 1/20th points. In certainsituations, this information may be useful as backup. The listings provide information similarto what is shown on the Results graph. The one difference is that there is a listing for Bal-anced Loading but there is no listing for deflections.

To include an item from either tab on the report, check the box next to the item. Afterselecting the desired items, an updated report may be generated by clicking on theRepaginate button. The selections will be retained and used for future runs and projects. If achecked item contains information which comes from a post-processor that has not been run,the program will prompt the user to run the post-processor.

2.6.2 Report Heading

The first page of the Results Report shows the user’s Company name and address. This maybe changed via the Pagination Setting button on the Report Setup screen or the PaginationSetup item on the Options Menu.

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FIGURE 2.6.1-2

2.6.3 Viewing and Printing the Results Report

To view the Results Report on the screen, select Results Report from the View Menu or clickon the View Results button on the Main Toolbar. The report displayed will include themost recently selected data blocks.

To print the Results Report, click on the Print button on the Main Toolbar or select thePrint item on the File menu in the Main Program window while the Results Report is theactive window.

2.6.4 Viewing and Printing Results Graphs

The seven Results Graphs are as follows:

• Bending Moments,• Shears,• Rebar,• Deflection,• Stresses,• Post-tensioning required/provided, and;• Tendon Height.

To view the Results graphs, either click on the Show Graphs button on the Main Toolbaror select the Graphs item on the View Menu. The Show Graphs button will open all thegraphs; the Graphs item will allows the user to either show all graphs or pick a specific graph.

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The graphs display information at 1/20th points along the spans. Figure 2.6.4-1 shows aResults Graph for stresses due to the Service Load Combination. The check boxes on the leftside of the graph allow the user to specify what spans and/or what information should bedisplayed.

FIGURE 2.6.4-1

Default graph properties can be set via the Graph Properties item on the Options Menu. Tocustomize a particular graph, right-click on the graph to bring up a formatting menu. Theformatting menu provides a number of options including the option to maximize the graph tofull screen, mark the data points or show the data values at a specified precision. (Theformatting menu is the same for the Recycle Window graphs).

To print a graph, select either the Print item on the File Menu in the Main Program window or

the Print button

on the Main Toolbar while the graph is the currently active window.Graphs may be printed either in portrait or landscape orientation. Graphs may also be ex-ported as a bitmap file (.BMP) or Windows metafile (.WMF). A default bitmap size can beset via the Graph Properties item on the Options Menu.

There is another, more extensive export option on the right mouse menu. Figure 2.6.4-2shows the Export Dialog options on this menu.

2.6.5 Printer Setup

The Page/Print option on the File Menu in Main Program window allows the user to selectthe printer, paper size, orientation and margins for the Results Report and Results Graphs.

2.6.6 PT Summary

The PT Summary Report is a one-page graphical report which summarizes the post-tension-ing and mild steel reinforcing requirements. To create the PT Summary Report, either select

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the PT Summary item on the View Menu or the Open PTSum button on the MainToolbar. The PT Summary Report is discussed further in Section 3.1.

2.7 PRINCIPAL OUTPUT FILES

At the completion of the analysis, the program generates a set of temporary output files, then returnsto the Main Program window. The output files, stored in the same subdirectory as the input files, areas follows:

RESULTS.DATThis file contains the data shown on the most recently generated Results Report. Dependingon what has been selected, it may include input data and some or all of the output datablocks. Section 2.6.1 describes how to set up this report and select the items that areincluded in this file. Sample printouts of this file are given in Chapters 5 and 6 of the Softwaremanual. If the project is saved via one of the Save As options in the Main Program window,the RESULTS.DAT file is renamed to *.CRE.

The user may also find it helpful to examine the following files which contain information at 1/20th points along the span. These files are straight text files so they may be viewed in any texteditor. They may also be appended to the Results Report by selecting the appropriatebox(es) on the Detailed Output tab of the Report Setup screen.

MOMENTS.DATThis file contains a listing of moments at 1/20th points along the span due to dead load, liveload (minimum and maximum), post-tensioning balanced moments, and secondary moments.

SHEARS.DATThis file contains a listing of shears at 1/20th points along each span due to dead load, liveload (negative and positive), post-tensioning balanced loading, and secondary loading.

FIGURE 2.6.4-2

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FACBMSF.DATThis file contains a listing of factored moments and shears at 1/20th points along the member.The load factors are those specified by the user for the Strength (Ultimate) load case duringdata input.

STRESSES.DATThis file contains a listing of stresses due to dead load, live load (maximum tension andcompression), post-tensioning balanced loading and the service stress combination selectedby the user during data input. Stresses at the top and bottom of the member are listed at 1/20th points along the span.

WBAL.DATThis files contains a detailed listing of the Balanced Loading. The file is organized in much thesame manner as the loading file created by the user during data input; it lists all of the loadingsimposed on the structural model by the selected tendon profile.

PTREQ.DATThis file contains a listing of the post-tensioning force required at 1/20th points along eachspan according to the final tendon profile.

REBAR.DATThis file contains a listing of the rebar required for the Strength (Ultimate) load case at 1/20th

points along each span. It lists both the factored moments and the top and bottom rebarrequired.

PTCGS.DATThis file contains a listing of the tendon height above the reference line at 1/20th points alongeach span.

2.8 SAVING PROJECTS

To save a project so that it can be accessed in the future, select either Save As from the File menu inthe Main Program window or click on the Save As button on the Main Toolbar. The file name anddirectory can be different from what was used when saving the input files.

The screen for saving projects is shown in Fig. 2.8-1. To save the project as an ADAPT Version 5.xfile, click on the down arrow next to the ‘Save as type:’ box and select “ADAPT-PT (old)(*.PT)”.

The files saved through the Save As command are:

*.ADB,*.CRE*.PT, *.CGE, *.CLD, *.CCR

*.PTX, OPT, *.LAT

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FIGURE 2.8-1

The first file *.ADB contains all of the input data, except the data for the post-processors. This file isall that is required to re-load and re-execute the analysis for a project.

The file *.CRE contains the information displayed on the most recently generated Results Report.The *.CRE file is an ordinary text file and can be opened in a word processor for additional editing orformatting.

The files *.PT, *.CGE, *.CLD, *.CCR are saved for backward compatibility with ADAPT-PTversion 5.xx programs. They are not used in the current version.

The file *.OPT contains the information for the Initial Stresses and Stresses post-processors. Thefile *.LAT contains the information for the Lateral Analysis post-processor. The file *.PTX containsthe user-specified tendon profile and forces. This information is used if the “Recall” button is in-voked to restore the previously specified profile and forces.

Note:

The save options in the Input Editor (the Save and Save As commands on theFile menu, the Execute option, the Save buttons) only save the input files. Theproject must be saved from the Main Program window in order to view theResults Report without re-executing the analysis or open it in a word processor.

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2.9 TENDON SELECTION MODE

If the Force/Tendon Selection option was chosen during input, the user may choose between theForce and Tendon Selection modes in the Recycle window. The difference between the two modesis discussed in Section 1.1. The Force Selection option is the design method commonly used inNorth America. It assumes that a tendon will be assigned a final and constant effective force equal tothe jacking force minus all stress losses expressed as a single representative value. The TendonSelection method is a newer, more accurate procedure. In the Tendon Selection method, the post-tensioning force is assumed to vary along the length of the tendon. The variation accounts for stresslosses in the tendon due to both immediate and long-term effects. It also includes consideration of theinteraction between the various sources of loss. It is thus more accurate than procedures whichaccount for losses as a lump sum approximation.

2.9.1 Overview

In Tendon Selection mode, the actual number of strands, as opposed to effective forces, maybe specified. The user is able to see what the final stresses will be and can adjust the numberof strands, the tendon profiles and the stressing ends as necessary. At each design sectionalong a span, the program performs an analysis based on the post-tensioning force at thatsection. Consideration is given to both short-term (friction, seating loss, elastic shortening)and long-term (creep, shrinkage, relaxation of the prestressing steel) stress losses.

If the tendon profile is altered, friction and long-term losses are recalculated and the revisedtendon forces are used for the computations. If the tendon forces have changed significantlyhowever, the selected profile may not be satisfactory. The solution thus becomes iterativesince subsequent changes to the profile will also result in changes to the tendon forces. Theiteration is automatically continued until an acceptable solution is reached.

2.9.2 Description of Features

Tendon types

For each member, up to three tendon types A, B, and C, may be specified. Each typecan be configured to have a different length and different stressing/fixed ends. A giventendon type may include one or more strands.

Figure 2.9.2-1(a) shows a five span beam with three different tendon arrangements.Tendon A extends the entire length of the beam and is stressed at both ends. It is shownin Fig. 2.9.2-1(b) as a straight line with two arrowheads representing the stressing ends.

The other two tendon types, B and C, start at either end of the beam and extend onlypart way through the member. The short vertical lines signify a fixed (non-stressing) end.

Figure 2.9.2-1(c) illustrates the shapes that the different tendon types can assume.Tendon type A must extend from one end of the member to the other. It can be stressedat one or both ends. Tendons types B and C can be configured the same as A, the sameas one another, or completely different. They can be stressed at one or both ends andthey can start and end anywhere in the member as long as it is possible to stress them.

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Under normal conditions, the three tendon types will be configured differently. A post-tensioned member may not need all the three tendon types, however. Many membershave only a Type A tendon. Type B and C tendons are typically configured to provideadditional post-tensioning in end spans if necessary.

FIGURE 2.9.2-1

The number of strands in each type of tendon, and consequently the force in each tendonwill usually be different. All the tendons are assumed to follow the same profile, how-ever. I.e. if a reversed parabola profile was specified during data input, all tendons are

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assumed to have a reversed parabola profile with the same high and low points along themember. The one exception is where tendons terminate at the interior of a member (Fig.2.9.2-2). The end anchorage or stressing point is assumed to be at the centroidal axis ofthe section where the tendon terminates. Note that this restriction does not apply to thetendons terminating at the ends of the post-tensioned member. At the ends of the mem-ber, tendon heights are as specified on the Tendon Force and Heights tab. Although

FIGURE 2.9.2-2

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tendons are usually terminated at the centroid of the section, they may be specified withan eccentricity.

Stress Loss Calculations

There are two types of prestress losses: immediate losses which occur at the time thetendon is stressed and long-term losses which may continue for several years. The finaleffective force in the tendon is the jacking force minus all losses.

The immediate losses, friction and anchorage seating, are calculated based on the user-input friction parameters together with the tendon’s profile and stressing configuration.The stress in the tendon immediately after it is seated, with due allowance for friction andseating loss, is referred to as the initial or lock-off stress. Although friction coefficientsare different for grouted (bonded) and unbonded systems, the friction loss computationsare essentially the same.

There are three options for long-term stress loss calculations:

Lump sum entryA lump sum value may be calculated by the user and entered during datainput. The effective stresses in the tendon are calculated by subtracting thisvalue from the initial stresses. Since the friction and seating losses cause theinitial stresses to vary along the tendon, the effective stresses will also vary.

Long Term Loss calculations for unbonded tendonsFor unbonded tendons, the strain in the tendon at any given point is notdirectly related to the local strain in the concrete. The program can calcu-late an average long-term loss value for the entire tendon based on theaverage precompression in the member and expected losses due to shrink-age, creep, elastic shortening and relaxation of the prestressing steel. Theeffective stresses in the tendon are calculated by subtracting the averagelong-term loss value from the initial stresses.

Long Term Loss computation for grouted tendonsLong-term stress losses in grouted tendons are a function of the local strainin the concrete. Long term-losses are thus computed at 1/20th points alongthe tendon. The effective stress at each point is the jacking stress minus thefriction, seating loss and long-term stress losses at that point. The long-termlosses are stored in the file LTLOSS.DAT. This is a text file and can beviewed with any text editor or word processor.

2.9.3 Data Input for Long-term Stress Loss Calculations

In order to be able to use Tendon Selection, the Force/Tendon Selection option on theCalculation Options screen must be selected during data entry. If Force Selection is chosen,the program will only allow Force Selection to be used in the Recycle window. If Force/

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Tendon Selection is chosen, the user may toggle between the two options in the Recyclewindow.

Figure 2.9.3-1 shows the Calculation Options screen. The section of the screen for Calcula-tion of friction and long-term losses is only displayed if Force/Tendon Selection/FrictionCalculations is chosen. This section of the screen allows the user to specify the friction andlong-term loss parameters. Note that long-term losses may either be calculated by theprogram or entered as a lump sum value. Additional information on input parameters forprestress loss calculations is given in Section 3.4.

FIGURE 2.9.3-1

2.9.4 Description of Execution

Execution of this option is similar to the standard program execution except that the user isable to select the Tendon Selection option. The default mode is Force selection. To useTendon Selection, the user must click on the Tendon Selection option in the Recycle window(Fig. 2.9.4-1.)

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FIGURE 2.9.4-1

The Tendon Selection & Extents tab becomes active when the Tendon Selection mode ischosen. The left side of the tab shows the average force in each strand and the number ofstrands required and selected for each tendon type. The average force in each strand is theforce after all losses. Note however that the average forces are not actually used in thecalculations. They are displayed to provide the user with a measure of the relative efficiencyof each strand type.

The right side of this screen shows a symbolic representation of the spans and the tendonlayout. The default layout is a Type A continuous tendon stressed at both ends of the mem-ber, a Type B tendon stressed from the left and extending over the leftmost span and a type Ctendon stressed from the right and extending over the rightmost span.

The user can edit the post-tensioning layout by:

Adjusting the tendon profilesTendon heights are edited on the Tendon Force & Heights tab. Note thatwhen the Tendon Selection option is active, the user cannot access the Forcecolumn on this tab. In the Tendon Selection option, forces are calculatedbased on the number of strands and the final stresses in the strand.

Editing the number of strands in a tendon typeThe number of strands to use for each tendon type is shown in the SelectedNumber column. These numbers may be changed independently of oneanother. To delete a tendon type, set the number of strands selected to zero.To add a tendon type, enter the number of strands to use for that type.

Changing the stressing ends and/or extent of the tendonsTo change a tendon end from dead to stressing or stressing to dead, hold down

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the Shift key and left click once at the end of the tendon. Clicking a secondtime will change the tendon back to its original configuration. Note that thetendon must have at least one stressing end. To change the extent of a Type Bor C tendon, position the cursor over the tendon end, hold down the left mousebutton and drag the end to the desired location.

If any changes are made to the tendon profiles or number of strands, the window must berecycled to recalculate the force provided. There is no limit on the number of changes thatcan be made or the number of times the window can be recycled. Once an acceptable post-tensioning layout has been determined, select Exit to continue with the calculations.

Clicking on the Force Selection button at the top of the Recycle Window will toggle theprogram back to the Force Selection mode. Any changes that have been made while in theTendon Selection mode will be reflected in the forces shown on the Tendon Force & Heightstab.

2.9.5 Differences in Long Term Stress Loss Computations

Long-term stress loss calculations are different for grouted and unbonded systems since thestress loss for grouted tendons is a function of the local strain in the concrete. They are alsodifferent for pre- and post-tensioned members.

As noted above, an average long-term stress loss is usually calculated for unbonded tendons.For bonded strands that are pre-tensioned, many engineers use a lump sum value based onstress losses at the location of maximum moment. Pre-tensioned members are typicallysimply supported, they generally have only one critical moment location and the strands areoften straight. Calculating the stress loss at only one location may therefore be acceptable. Itis typical not acceptable for post-tensioned systems with profiled strand, however. Losses atmid-span and over the supports may be widely different and both sections may be stresscritical.

In order to calculate long-term stress losses for a grouted system, a detailed strain computa-tion must be done along the path of tendon. A listing of strains at 1/20th points is onlyavailable when ADAPT is executed in the Tendon Selection mode. If a friction and long-termlosses calculation needs to done for a grouted system designed with Force Selection, a lumpsum must be entered for long-term losses.

The theoretical background for the elastic shortening and long-term stress loss calculations isgiven in Section 3.4.

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Post-Tensioned SlabSan Francisco Bay - California

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ADAPT PT SUMMARY REPORT AND POST-PROCESSORS

LIST OF CONTENTS

3.0 PT SUMMARY AND POST-PROCESSORS ........................................................ 3-1

3.1 PT SUMMARY REPORT........................................................................................ 3-33.1.1 PROGRAM DESCRIPTION .......................................................................... 3-33.1.2 PROGRAM EXECUTION ............................................................................. 3-43.1.3 DESCRIPTION OF THE OUTPUT ................................................................ 3-7

One-Way Shear ............................................................................................ 3-8Punching Shear ............................................................................................ 3-8

3.1.4 EXAMPLE PRINTOUT – THREE SPAN BEAM ............................................ 3-93.1.5 EXAMPLE PRINTOUT – THREE SPAN, TWO-WAY SLAB ........................ 3-10

3.2 INITIAL STRESS ANALYSIS ............................................................................... 3-113.2.1 BACKGROUND AND THEORY.................................................................. 3-11

Stress Check at Time of Transfer of Prestress (Initial Conditions) ................ 3-12Stress Check for Members Designed with High Live Loading ..................... 3-12

3.2.2 IMPLEMENTATION OF THE INITIAL STRESS CHECK .............................. 3-123.2.3 DESCRIPTION OF FILES AND PRINTOUT ................................................ 3-14

Initial Stress Check Summary (INITIAL.DAT) ............................................... 3-14Stresses At 1/20th Points (INSTRS.DAT) .................................................... 3-15Steel Required Due To Stress Check (INISTL.DAT) .................................... 3-16

3.2.4 EXAMPLE - TWO-SPAN T-BEAM ............................................................. 3-183.2.5 VERIFICATION ........................................................................................... 3-23

Data Block 14.1 - Parameters Specified As Input For Initial Stress Checks. 3-23Data Block 14.2 – Additional Mild Reinforcement Required ........................ 3-23Data Block 14.3 - Compressive Stresses ................................................... 3-25

3.2.6 SPECIFIC FEATURES OF VERSIONS OTHER THAN ACI ........................ 3-26

3.3 LATERAL ANALYSIS .......................................................................................... 3-273.3.1 BACKGROUND ......................................................................................... 3-273.3.2 ANALYSIS PROCEDURE .......................................................................... 3-293.3.3 INPUT SCREENS ...................................................................................... 3-323.3.4 DESCRIPTION OF PRINTOUT ................................................................... 3-33

3.3.4.1Summary of Moments - file LATBM.DAT .......................................... 3-34Data Block 15.1 ............................................................................... 3-34Data Block 15.2 ............................................................................... 3-34Data Block 15.3 ............................................................................... 3-34Data Blocks 15.4, 15.5 .................................................................... 3-34

3.3.4.2 Summary of Moments - file LATBM.DAT ......................................... 3-353.3.4.3 Summary of Mild Reinforcement - file LATSTL.DAT ......................... 3-35

3.3.5 EXAMPLES ............................................................................................... 3-36EXAMPLE 1 - TWO-WAY EQUIVALENT FRAME ANALYZED FOR WINDLOADING ................................................................................................... 3-36EXAMPLE 2 - T-BEAM ANALYZED FOR EARTHQUAKE LOADING ......... 3-36

3.3.6 VERIFICATION ........................................................................................... 3-49

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ADAPT PT SUMMARY REPORT AND POST-PROCESSORS

Data Block 15.1, Calculated Factored Span Moments Mu .......................... 3-62Data Block 15.2 .......................................................................................... 3-63Data Blocks 15.3 Through 15.5................................................................... 3-64

3.3.7 DISCUSSION OF LATERAL LOADING TREATMENT ................................ 3-663.3.8 SPECIFIC FEATURES FOR CODES OTHER THAN ACI .......................... 3-70

3.4 FRICTION AND LONG TERM LOSSES POST-PROCESSOR .......................... 3-713.4.1 BACKGROUND ......................................................................................... 3-713.4.2 STRESS DISTRIBUTION ............................................................................ 3-723.4.3 FRICTION AND SEATING LOSS CALCULATIONS .................................... 3-773.4.4 LONG-TERM STRESS LOSS PARAMETERS ........................................... 3-833.4.5 DESCRIPTION OF PRINTOUT ................................................................... 3-883.4.6 NOTATION .................................................................................................. 3-92

3.5 USER STRESS COMBINATION ......................................................................... 3-93

A.1 REFERENCES .................................................................................................... 3-94

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ADAPT PT SUMMARY REPORT AND POST-PROCESSORS Chapter 3

3.0 PT SUMMARY AND POST-PROCESSORS

After the analysis is executed, there are four optional post-processors which can be run Inaddition, a graphical summary report can be generated. To invoke these options, you mustexit from the Recycle window. The program will continue with the calculations, then returnto the Main Program window. At this point, you can view and print the Results Report andResults Graphs. You can also run the PT Summary Report and the post-processor programs.The four options are described briefly below. This is followed by a detailed description ofeach.

PT Summary Report

The PT Summary module enables the user to generate a flexible and compact graphicalreport for each ADAPT run. The report summarizes all post-tensioning parameters, rebarrequirements, and shear checks from a computer run on a single page of output. The format-ted report may be viewed on the screen, then printed, saved as a Drawing Exchange (.DXF)file or copied to the Windows clipboard as a (.CLP) file.

The report is designed for professionals involved in the design, construction, or managementphases of a project who need a compact, readily accessible summary of the post-tensioningand mild steel requirements. It does not show analysis results, design actions or deflectioncalculations. This information is available on the Results Report and Results Graphs.

Post-Processors

The four post-processors are:

• Friction and Long Term Losses;• Initial Stresses;• Lateral Analysis; and,• Stresses.

Information for the Friction and Long Term Losses post-processors is entered during datainput. If the Force/Tendon Section | Friction Calculations button on the Criteria – CalculationOptions screen is chosen, additional input questions will appear.

Information for the Initial Stresses, Lateral Analysis and Stresses post-processors is enteredvia the Post-Processors item on the Action menu. Clicking on the ‘Set Values’ button to theright of an option will bring up the entry screen for that option. Figure 3.0-1 shows thescreen for entering Initial Stresses data.

To execute one or more of the post-processors, check the appropriate box or boxes and thenclick on Execute.

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FIGURE 3.0-1

The results of the Initial Stresses, Lateral Analysis and Friction and Long Term Losses post-processors can be included on the Results Report by checking the appropriate boxes on theReport Setup screen. If the box is checked before the post-processor is executed, the resultswill be automatically appended to the report. They can be appended to a previously format-ted report by checking the appropriate box on the Report Setup screen and then repaginating.The files that are generated by these post-processors are text files that can also be viewed in awordprocessor.

The post-processors can be executed automatically at the completion of the analysis byselecting the ‘Automatic Execution of Post-processors’ item on the Options menu. If thisitem is selected, all of the post-processors checked on the screen above will be automaticallyexecuted.

Initial Analysis

The Initial Stress Analysis allows the user to determine if additional mild steel reinforcing isrequired due to high stresses at the transfer of prestressing to the member

Lateral Analysis

The Lateral Analysis option allows the user to determine if additional mild steel is requiredfor lateral moments. The steel shown for the Lateral Analysis may be less than that requiredfor either minimum code requirement or the ultimate moment combination however. Theuser must check to determine what requirement governs.

Friction and Long Term Losses

The Friction and Long Term Losses post-processor calculates prestress losses for designs thathave been executed using the Force Selection mode. The analysis will calculate the stress inthe tendon at the left, center and right end of each span, the average initial stress, total long-term losses and the anchor set influence distance. It will also calculate required elongationsfor both one and two-ended pulls. If the tendon selection mode is selected the programautomatically calculates the friction losses and reports the associated results in its output.

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User Stress Combination

The User Stress Combination post-processor allows the user to graphically display thestresses resulting from various load combinations. The load combinations can be set at anyfraction of the live load, dead load and post-tensioned load.

The post-processor is intended as a serviceability check which is in addition to the ServiceLoad Combination used for the analysis. Note that the Stress Results graph is the only placethat the results are shown. The results of the analysis as shown on the Results Report are notchanged and there is no recalculation of the moments or required reinforcement.

3.1 PT SUMMARY REPORT

3.1.1 PROGRAM DESCRIPTION

To run the PT Summary module, select either the Open PTSum button on the MainToolbar or the PT Summary item on the View menu of the Main Program window.The PTSUM window will open up with a default format for the report. The windowis shown in Fig. 3.1.1-1.

FIGURE 3.1.1-1

The PT Summary report content is organized into independent data blocks whichinclude the following information:

• An elevation view of the member, including all drops and steps, with spanlengths and the post-tensioning tendon profile, including inflection points andlow points;

• Heights of tendon control points with respect to the reference line and the totalpost-tensioning force or total number of strands specified for each span;

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• Graphical representation of mild steel required in each span with a listing ofamounts and lengths of both top and bottom bars. There is also space to addadditional remarks for the rebar;

• Bar graph of the rebar required and provided at 1/20th points in each span;• For beams, a comprehensive graphical report of the shear reinforcing required

along the span and the maximum allowable spacing for the user-specifiedstirrup size;

• For two-way slabs, a report of the punching shear analysis at each column;• A summary of design parameters used in the analysis; and,• A section for designer notes.

The user can select which of the data blocks to print. In addition, the user can recal-culate the mild steel requirements using a bar size which is different from what wasinitially specified in the ADAPT run.

The PTSUM report can be viewed in final form on the screen. It can then be printedor saved as either a .DXF or clipboard file. If it is saved as a file, it can be insertedinto contract documents, calculation packages or structural drawings.

3.1.2 PROGRAM EXECUTION

The report may be printed in color or black-and-white, portrait or landscape, and on avariety of paper sizes. After the data blocks are selected, the report is automaticallyrescaled to fit the specified paper size.

The Zoom buttons on the PTSum Toolbar can be used to adjust the size of the reporton the screen. There are also Zoom In and Zoom Out options on the PTSum ViewMenu.

Report SetupTo specify what information to print, select the Report Setup item on the View menuor click on the Report Setup button on the PTSUM Toolbar. A window with threetabs will appear. Figure 3.1.2-1 shows these three tabs.

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• Use the check boxes on the ‘Sections to be printed’ tab to select which datablocks to print.

• Use the ‘Rebar Selection’ tab to change the bar sizes or bar system used fortop and bottom reinforcing steel.

• Use the ‘Designer’s Notes’ tab to input notes that will be printed at the bottomof the report.

FIGURE 3.1.2-1

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Click on the Apply button to apply the selected options to the report. To format thereport to include only certain spans, use the Spans button on the PTSUM Toolbar.The Refresh item on the PTSum View Menu will reformat the report to include allspans.

To specify color or black-and-white, select the Color Setup item on the View Menu orclick on the Color Setup button on the PTSum Toolbar. This will change the colorsetup on both the screen and the printout.

Print SetupTo specify the printer, set the margins or set the orientation of the report, select thePage Setup item on the File Menu. To just need to set the orientation of the report,select the Page Setup item on the File Menu or click on the Page Setup button on thePTSum Toolbar. To print the report, select either the Print item on the File Menu orthe Print button on the PTSum Toolbar.

Save as DXF file/ Exporting to the ClipboardTo save the report as a drafting (.DXF) file or export it to the clipboard, the reportmust first be set up with the desired information and in the desired format.

To save the report as a drafting (.DXF) file, select the ‘Save As DXF’ item on the FileMenu or click on the ‘Save as DXF’ button on the PTSum Toolbar. To export thereport to the clipboard, select the Copy item from the Edit Menu or click on the Copybutton on the PTSum Toolbar. This will save an image of the report on the Windowsclipboard. The image can then be pasted into another file or the Windows clipboardviewer can be used to edit and save the file.

More on Rebar SelectionThe bar system used for the ADAPT-PT analysis is determined according to thedesign code selected during data input. The preferred bar size is also specified duringdata input. Although these will be used as defaults for the PTSum report, both thebar system and bar size can be changed.

All of the bars systems shown on the Rebar Selection tab (ASTM - US Customary,ASTM - US SI, Euro or CSA) are available, no matter what design code was used forthe ADAPT-PT run. First, select the desired bar system. Then, specify the top andbottom bar size from the pull-down list of bar sizes available for that bar system.Click on Apply to recalculate the mild steel reinforcing requirements with the new barsizes.

To go back to the bar system and sizes in the original ADAPT-PT run, select the ‘UseInput Data as Default’ option. Click on Apply to recalculate the number of barsrequired.

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3.1.3 DESCRIPTION OF THE OUTPUT

The following is a description of the data blocks that can be included:

Data Block 1This data block contains the General and Specific titles entered during data input.

Data Block 2 – Member ElevationThis data block contains an elevation view of the member with span dimensions. Italso includes a graphical representation of the tendon profile that shows inflectionpoints and low points.

Data Block 3 – Top RebarThis data block reports the amount and length of rebar required at the top of themember. The rebar shown is the larger of the steel required to withstand the negativemoment demand and code specified minima.

If the steel required is controlled by the negative moment demand, the bar lengths arebased on the required rebar quantities at 1/20th points. The selected rebar is calculatedas two lengths in an effort to minimize material requirements. This is particularlyhelpful for cases where rebar requirements vary and a large amount of reinforcing isrequired over a short section of the span. In the cases, using bars that are all the samelength bars might be an unnecessary waste of materials.

Note that the steel selected by the program is only one acceptable design solution.Space has been provided in this data block for the designer to provide alternateinformation on rebar quantity, size and length. The designer may also use this spaceto write in any additional notes or remarks pertaining to the rebar.

Data Block 4 – Tendon ProfileData Block 4 shows an elevation view of the tendon profile. Tendon control pointsare marked and their heights with respect to the reference line are given. If the com-puter run was done in the Force Selection mode, the program shows the total post-tensioning force in each span. If the Tendon Selection option was used, the elevationview also includes the total number of tendons, the location of all dead and livestressing ends, and any added tendons (see Section 2.9 for more information on theTendon Selection mode).

Data Block 5 – Bottom RebarThis data block reports the amount and length of rebar required at the bottom of themember. The format is the same as Data Block 3 – Top Rebar.

Data Block 6 – Required & Provided BarsThis data block plots the rebar required and provided for the top and bottom of thesection at each 1/20th point. The maximum required areas of steel required for the topand bottom of each span are also shown.

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Data Block 7 – Shear Bars / Punching ShearThis data block shows one-way shear results for beams and one-way slabs. For two-way slabs, it shows punching shear results.

One-Way Shear

For beams and one-way slabs, this data block reports the stirrup size andspacing based on user input during data entry. The spacing shown is themaximum spacing along the different segments of the span. The data blockalso includes a bar graph of the area of shear reinforcement required alongeach span.

This block is typically not included on reports for one-way slabs since shearreinforcement is seldom required. Although this block may indicate that shearreinforcement is required at the supports for a one-way slab, a review of theResults Report will show that this is for beams only.

Punching Shear

For two-way slabs, the data block plots an elevation view of the model, whichindicates the punching shear stress ratio at each support and states whether thestress ratio is acceptable per the specified code.

Data Block 8 – LegendThis data block identifies the symbols used to indicate stressing and dead ends. Note,however, that the stressing and dead ends are only shown when the Tendon Selectionoption has been used for the analysis. The legend is not applicable if Force Selectionwas used.

Data Block 9 – Design ParametersThis data block reports the following design parameters used in the ADAPT-PT run:

• Design Code;• Concrete strength; f’

c,• Mild steel yield strength; fy,• Ultimate tendon strength; fpu,• Minimum Top and Bottom rebar cover;• Rebar Table;• Tendon jacking stress; fpj and,• Tendon strand area.

Data Block 10 – Designer’s NotesThis data block contains notes added by the designer. The entry in this box will beused on future runs and future projects until it is cleared. To clear the notes, selectClear and then click on Apply.

3 - 9


3.1.4 EXAMPLE PRINTOUT – THREE SPAN BEAM

The following is a design summary for the three-span beam example in the SoftwareManual (MNL5-3M). The Tendon Selection method was used for design. Thereport was printed in landscape orientation.

ADAPT - ST RUCTURAL CO NCRETE S O FTW ARE SY STEMADAPT-PT Version 6.08 Date: 10 /11/00 Tim e: 10:02 :20 AM File : Mn l5_3_L

1- P ROJE CT TITL E A DAP T PT M anual1.1 DESIGN STRIP T-BEAM EXAMPLE FOR ADAPT POST TEN SION IN G SO FTW ARE

2 - MEMBE R ELEV AT IO N

[ft] 64 .0 0 55 .00 1 7. 00

3 - TOP RE BA R

3.1 User selected

3.2 User selected

3.3 ADAPT selected

3.4 ADAPT selected 3 9# 5X3 4'6"1 4 #5 X1 8'0"

4 9# 5X 17'0 "2 4 #5 X5 '6 "

7 4# 5X3 1'6"

8 4#5 X2 3'0"

4 - TEND ON PRO FILE

4.2 Da tum Line4.3 CGS Distance [in]4.5 Force

23 .00 3.2 5 3 1.0 0[3 73 kips]

3 1.0 0 3 .25 31 .00[ 20 8 kip s]

31 .0 0 22 .0 0 23 .00[ 208 kip s]

5 - BOTTOM REBA R

5.1 User selected

5.2 User selected

5.3 ADAPT selected

5.4 ADAPT selected 5 3 #8 X5 3'6"

6 3 #8 X4 7'0"

9 2# 8X 38 '0 "

10 1# 8X 32 '6 "

11 3# 8X6 '6 "

6 - REQU IR ED & P ROV IDE D B A RS

6.1 Top Bars

[ in2]

requ ired provided

6.2 Bottom Bars

max

max

0 .0

2 .8

5 .6

2 .4

4 .8

5 .5 2

3 .9 8

4. 91

1. 64

2. 41

1. 64

7 - SHE AR STIRRU PS7.1 ADAPT selected. Bar S ize #6 Legs: 2 Spacing [in] - 2 4 - 24 - 24 - 2 4 - 24 -

7.2 User-se lected Bar S ize # Legs:

7.3 Requi red area

[in2/ft]

0 .00 00 .01 80 .03 60 .05 40 .07 2

.0 7 .07 0

8 - LEGE ND Stressing End Dead End

9 - DES IGN PA RA ME TE RS9.1 C ode: ACI f'c = 4 ksi fy = 60 ksi (longitudina l) fy = 60 ksi (shear ) fpu = 270 ksi

9.2 Rebar Cover: Top = 2 in Bottom = 3 in Rebar Tab le: ASTM - US Customary bars (Non-red istr ibu ted Moments)

9.3 S tressing : fpj = .8 fpu

9.4 S trand A rea = .153 in2

10 - DE SIGNE R'S NOTE S

FIGURE 3.1.4-1

3 - 10


3.1.5 EXAMPLE PRINTOUT – THREE SPAN, TWO-WAY SLAB

The following is a design summary for the three-span, two-way flat slab exampleprovided in the Software Manual (MNL5-2M). The Force Selection method was usedfor design.

ADAPT - ST RUCTU RAL CO NCRETE SO FT W AR E SYS TEMADAPT-PT Version 6 .08 Date: 9/29/00 Time: 2 :33:3 3 PM File : Mn l5_2m _L

1- PROJECT TITL E ADAPT PT Manu al1 .1 D ES IGN STRIP Two-way equiva len t frame slab examp le fo r AD APT (SI)

2 - MEM BER E LEV AT IO N [m ] 5. 75 0 8 .2 00 6. 75 0 0 .90 0

3 - TOP R EBA R

3.1 U ser se lected

3 .2 U ser se lected

3 .3 ADAPT se lected

3 .4 ADAPT se lected 2 1 1-16 mm X4 38 0 mm1 6 -1 6m m X 20 40 mm

3 11 -1 6m m X 20 00 mm

4 1 2-16 mm X4 68 0 mm

5 11 -1 6m m X21 00 mm

7 7-1 6m m X 318 0 mm

4 - TENDON PROFILE

4.2 D atum L ine

4 .3 C GS Distan ce [mm]4 .5 F orce

13 0 2 5 23 5[1 23 8 kN ]

2 35 2 5 2 35[ 12 38 kN ]

23 5 2 5 15 0[1 65 0 kN ]

1 50 1 35 13 0[1 65 0 kN ]

5 - BOTTOM R EBAR5.1 U ser se lected



5 .4 ADAPT se lected 6 9 -1 6m m X 34 80 mm 8 4-1 6mm X3 30 0 mm

9 4-1 6mm X2 62 0 mm

6 - RE QUIRED & PROVIDED BARS

6.1 T op Bars

[ mm2]

r eq uired p ro vided

6 .2 Bottom Bars

max

max

0 0E +0 0

1 2E +0 2

2 4E +0 2

3 6E +0 2

4 8E +0 2

9 0E +0 11 8E +0 2

3 77 7

89 7

4 53 3

1 71 5

4 35 8

1 41 2

1 31 6

0

7 - PUNC HING SH EAR OK=Acceptab le

NG =N o Good *=n ot appli cable

or not pe rformed

- --

*

.65

OK

.65

OK

-- -

*

7 .1 S tress Ra tio

7 .2 S tatus

8 - LEGEND Stre ssing End Dea d End

9 - DE SIGN PARAMETERS9.1 Code : AC I f'c = 28 N/m m

2 fy = 460 N /m m

2 (longi tud in al ) fy = 460 N/m m

2 (shear) fpu = 1860 N/mm

2

9 .2 R ebar Cover: T op = 2 5 mm Bo ttom = 25 mm Rebar Table: ASTM - US S I bars (Non-red istributed Mom ents)

9 .3 S tressing: fpj = .8 fpu

9 .4 S trand Area = 99 mm2

10 - D ES IGNE R'S NOTES

FIGURE 3.1.5-1

3 - 11


3.2 INITIAL STRESS ANALYSIS

The Initial Stress Analysis allows the user to determine if additional mild steel reinforcing isrequired at force transfer of prestressing to concrete.

Stress checks can be performed for any loading, post-tensioning, or concrete strength condi-tions. Several stress checks may need to be performed for a given design. For each stresscheck, the user enters the ratio of the initial to specified concrete strength, initial to specifiedpost-tensioning force and the fraction of dead and live load. The screen for entering thesevalues is shown in Fig. 3.2-1.

FIGURE 3.2-1

3.2.1 BACKGROUND AND THEORY

In post-tensioned members such as mat foundations and transfer girders, the post-tensioning is usually applied before the member is subject to its full design loading.Since the post-tensioning is generally determined for the design loading, its transferprior to the application of the total loading can result in stress distributions which aresignificantly different from the final service conditions. In addition, in memberswhere the ratio of live loading to self weight is very high, the presence or absence oflive loading can have a significant impact on the member response. Substantialchanges in stresses can occur depending on the loading.

Stage stressing the tendons as the loading is applied can reduce the stress extremes format foundations and transfer girders. It is not a solution for members with high liveloading or other unusual loading conditions, however. In these cases, it may benecessary to provide additional mild steel to resist the tensile stresses.

In a member where there will be significant changes in loading, stresses for each ofthe extreme loading cases should be reviewed. Typically, the post-tensioning is de-signed for the full loading condition. If stresses for other potential loading conditionsexceed the allowable tensile limits, addition rebar should be provided for crackcontrol. The two most common stress conditions that need to be checked are:

3 - 12


Stress Check at Time of Transfer of Prestress (Initial Conditions)

At the time of the prestress transfer, the concrete is usually between three andfive days old and therefore is only 60 to 75% of its design strength. In addi-tion, the post-tensioning is higher than the design value since long-term losseshave not occurred and in most cases, live loading is absent. The followingtable gives the typical ratios of these parameters at initial condition to theirrespective design values:

In this case the allowable stress against which the member is checked will beallowable service stresses. The allowable service stresses are different fromthose used for initial condition check.

3.2.2 IMPLEMENTATION OF THE INITIAL STRESS CHECK

The user can enter a different set of parameters for each stress check. The followingcomputations are performed:

• The dead loading, live loading, post-tensioning and combined stresses at 1/20th points along each span are calculated using the combinations specified bythe user. The computed stresses are recorded in the file INSTRS.DAT.

• The combined stresses are compared with the allowable tension and compres-sion values based on the concrete strength and the stress limits specifiedduring data entry. For example, if the specified concrete strength was 4000 psi

Description Ratio Initial concrete strength ratio 0.75 Initial post-tensioning force ratio 1.15 Fraction of initial dead load 1.00 Fraction of initial live load 0.00

Stress Check for Members Designed with High Live Loading

Such members are generally designed for full live loading and then checkedfor stresses without live loading. The typical stress check parameters are asfollows:

Description Ratio Initial concrete strength ratio 1.00 Initial post-tensioning force ratio 1.00 Fraction of initial dead load 1.00 Fraction of initial live load 0.00

3 - 13


and the ratio of the initial to final concrete strength was 0.75, the tensile stresslimit for the condition shown in Fig. 3.2.2-1 would be: 3 * square root of(0.75*4000) = 164 psi.

FIGURE 3.2.2-1)

If tension stresses exceed the allowable values, the area of reinforcement required iscalculated. The following relationship (ACI 318) is used to calculate the requiredarea:

As = T/(0.5*fy)

Where:

As = Area of steel required;T = total tensile force of tension block; and,fy = yield stress of the steel but not more than 60 ksi.

The required area of steel due to initial stress conditions at each 1/20th point is re-corded in the file INISTL.DAT

• The calculated rebar is compared with that computed for the ultimate strengthrequirements and minimum code requirements as recorded in the fileSELBAR.DAT and summarized in data block 11 of the Results Report. If therebar required to satisfy initial stress condition exceeds that due to serviceconditions, the excess is recorded in the file INITIAL.DAT If rebar computedfor the initial stress check option does not exceed values already provided inthe original design (service condition), none will be recorded inINITIAL.DAT.

• If compressive stresses exceed the specified value, a warning will be dis-played. If this occurs, the original design should be modified. The status ofthe compressive stresses is recorded in the file INITIAL.DAT.

Important: although the ratio of initial to specified concrete strength is entered on thepost-processor screen, the allowable stresses are entered during data entry for theoriginal analysis. If you want to change the allowable stresses, you must edit theinput data and re-execute the analysis.

3 - 14


3.2.3 DESCRIPTION OF FILES AND PRINTOUT

The following describes the three principal files generated by the Initial Stress

Initial Stress Check Summary (INITIAL.DAT)

The results summary is stored in the file INITIAL.DAT which is a text file that maybe viewed with any word processor. The results may also be included on the ResultsReport as data block 14 by checking the Initial Stresses box on the Report Setup. Thesummary file lists:

• stress check criteria consisting of load combinations and strengthvalues;

• permissible stresses; and,• any required rebar which is in addition to the rebar reported for the

original design.

Figure 3.2.3-1 shows the summary file for the example of Section 3.2.4.

FIGURE 3.2.3-1

14 - I N I T I A L CONDITION STRESS CHECK & REINFORCEMENT REQUIREMENTS ============================================================================== 14.1 Parameters specified as input for initial stress checks: Tensile stresses divided by (f`c)^1/2 Concrete f`c (initial/final) .75 Top fiber ........ .25 PT force (initial/final) ... 1.15 Bottom fiber ........ .25 Dead loading (initial/final) 1.00 Live loading (initial/final) .00 Compression as ratio of f`c .... .60 Note: Reinforcement in this data block is in addition to that reported in data block II for minimum and strength reinforcement required by code. 14.2.1 NO added MILD REINFORCEMENT is required for G R O U P 1* 14.2.2 SELECTION OF REBAR G R O U P 2* (REFER TO 14.2.3 FOR POSITION) <------- TOP STEEL --------> <------ BOTTOM STEEL ------> JOINT (mm^2) <-- SELECTION --> (mm^2) <-- SELECTION --> --1---------2--------3---4------5-----------------6--------7---8------9------- 1 0 0 2 0 1534 3 #25 x 6600 mm 3 0 0 14.3 Compressive stresses COMPRESSIVE stresses are within allowable limit ( .60 * f`ci ) MAXIMUM stress.............................. = .44 * f`ci (f`ci = initial concrete strength) * Group 1 is generally in span and Group 2 at support. For exact location refer to the file INISTL.DAT.

3 - 15


Data block 14.1 reflects the user-input parameters for stress checks.

Data block 14.2 indicates the additional mild steel reinforcement required due toinitial stress conditions. The rebar shown is additive to the amounts shown in datablock 11 of the Results Report. Data blocks 14.2.1 and 14.2.2 indicate the area ofsteel required and bar selection for Group #1 and Group #2, respectively.

For common conditions, Group #1 refers to rebar required in span and Group #2refers to rebar at support. For unusual geometries or conditions however, user shouldrefer to the INISTL.DAT file for the exact location of the calculated reinforcement.

Data block 14.3 reports the maximum compressive stress as a multiple of the initialconcrete strength. Depending on the calculated maximum compressive stress, itdisplays a message saying either:

COMPRESSIVE stresses are within allowable limit ( — * f’ci)or,

W A R N I N G .....exceeded the specified limit ( — * f’ci)

Stresses At 1/20th Points (INSTRS.DAT)

This file, shown in Fig. 3.2.3-2, lists the stresses at 1/20th points along each span.The stress combination specified by the user is listed in the heading as:

Stress COMBINATION used is .... ( #.##DL + #.##LL + #.##PT)

Stresses at the top and bottom of the structure are listed separately for dead load, liveload, post-tensioning and the combination specified by the user. Stresses are onlylisted where applicable. If moments are reduced to face-of-support, only valueswithin the clear span length are displayed.

3 - 16


FIGURE 3.2.3-2

Steel Required Due To Stress Check (INISTL.DAT)

The rebar required due to the initial stress check at each 1/20th point is summarized inthe file INISTL.DAT. The values listed are due to consideration of the initial condi-tion, they are not additive to the steel from the original analysis.

This listing is useful for comparison with the steel provided for ultimate strength andthe minimum area of steel required by code. It can also be used as a guide to deter-mine where in the span the rebar should be placed.

Figure 3.2.3-3 is a partial reproduction of this file for the example of Section 3.2.4.

ADAPT STRUCTURAL CONCRETE SOFTWARE SYSTEM DATE: Sep 29,2000 TIME: 15:54 Data ID: MNL-INST Output File ID: INSTRS.DAT ============================================================================== SUMMARY OF BENDING STRESSES AT 1/20TH POINTS UNITS ARE ALL IN (N/mm^2) NOTE: stresses at centerlines, or next to centerline points may not be of practical significance if these points fall over the supports. Use the stresses which fall within the net span length as given at top of each table below. Where applicable, reduced moments are used. If live load (LL) is included, its maximum value at any point is used. Tension is shown positive. Stress COMBINATION used is .... ( 1.00DL + .00LL + 1.15PT) SPAN = 1 LENGTH = 20.00 meter (Net span from .46 to 19.54 m ) <--- D L ---> <--- L L ---> <--- P T ---> <-COMBINED-> X/L X top bottom top bottom top bottom top bottom ------------------------------------------------------------------------------- .00 .00 .05 1.00 -.94 1.88 -1.02 2.05 -2.17 -5.86 -3.43 -4.86 .10 2.00 -1.74 3.49 -1.92 3.85 -1.09 -8.01 -3.00 -5.72 .15 3.00 -2.41 4.83 -2.69 5.40 -.18 -9.84 -2.62 -6.49 .20 4.00 -2.95 5.90 -3.34 6.70 .58 -11.36 -2.28 -7.17 .25 5.00 -3.35 6.70 -3.87 7.75 1.18 -12.57 -1.99 -7.75 .30 6.00 -3.61 7.24 -4.27 8.56 1.63 -13.46 -1.74 -8.23 .35 7.00 -3.75 7.51 -4.55 9.12 1.91 -14.03 -1.55 -8.63 .40 8.00 -3.75 7.51 -4.71 9.43 2.05 -14.30 -1.40 -8.93 .45 9.00 -3.62 7.24 -4.74 9.49 2.02 -14.24 -1.29 -9.14 .50 10.00 -3.35 6.71 -4.65 9.30 1.84 -13.88 -1.24 -9.26 .55 11.00 -2.95 5.90 -4.43 8.87 1.43 -13.07 -1.30 -9.12 .60 12.00 -2.41 4.83 -4.09 8.19 .74 -11.67 -1.57 -8.59 .65 13.00 -1.74 3.49 -3.62 7.26 -.25 -9.70 -2.03 -7.66 .70 14.00 -.94 1.88 -3.04 6.08 -1.52 -7.15 -2.69 -6.34 .75 15.00 .00 .01 -2.32 4.65 -3.09 -4.01 -3.56 -4.61 .80 16.00 1.07 -2.14 2.48 -4.96 -4.94 -.30 -4.62 -2.48 .85 17.00 2.27 -4.55 2.63 -5.27 -7.09 4.00 -5.88 .05 .90 18.00 3.61 -7.23 3.34 -6.69 -9.52 8.87 -7.34 2.98 .95 19.00 5.08 -10.18 4.70 -9.42 -11.52 12.88 -8.17 4.63 1.00 20.00 SPAN = 2 STRESSES ARE SYMMETRIC TO SPAN 1

3 - 17


FIGURE 3.2.3-3

ADAPT STRUCTURAL CONCRETE SOFTWARE SYSTEM DATE: Sep 29,2000 TIME: 15:54 Data ID: MNL-INST Output File ID: INISTL.DAT ============================================================================== AREA OF STEEL REQUIRED DUE TO INITIAL STRESSES AT RELEASE Note: this is NOT in addition to rebar from other considerations Note: for LEFT CANTILEVER (if any) X/L= 0.00 is at tip of cantilever, and X/L= 1.00 is at first support SPAN = 1 LENGTH = 20.00 meter; CLEAR from .46 to 19.54 m X/L X <--Reinforcement (mm^2)--> m TOP BOTTOM ----------------------------------------------------------------------------- .80 16.00 .000 .000 .85 17.00 .000 .000 .90 18.00 .000 785.329 .95 19.00 .000 1533.735 1.00 20.00 SPAN = 2 LENGTH = 20.00 meter; CLEAR from .46 to 19.54 m X/L X <--Reinforcement (mm^2)--> m TOP BOTTOM ----------------------------------------------------------------------------- .00 .00 .05 1.00 .000 1533.735 .10 2.00 .000 785.329 .15 3.00 .000 .000 .20 4.00 .000 .000 .25 5.00 .000 .000

3 - 18


3.2.4 EXAMPLE - TWO-SPAN T-BEAM

This section contains an example of the use of the Initial Stresses post-processor to checkstresses at the transfer of post-tensioning. The structure is shown in Fig. 3.2.4-1. A partiallisting of the gravity design of this example containing the relevant information for the initialcheck condition is shown in Fig. 3.2.4-2. The solution to the stress check condition is givenin Fig. 3.2.4-2. Data block 11 of the Results Report, Mild Reinforcement Requirementsshows the steel required for the final design conditions. A summary of the Initial Stressoption requirements is given in data block 14.

FIGURE 3.2.4-1

Geometry and loading:

L = 20 mDead Load = 23.88 kN/mLive Load = 22.11 kN/m

Allowable stress at transfer of prestressing (initial stress):

Tension Stress = 0.25(f’)1/2

Compression Stress = 0.60(f’ci)

3 - 19


------------------------------------------------------------------------------ | ADAPT CORPORATION | | STRUCTURAL CONCRETE SOFTWARE SYSTEM | | 1733 Woodside Road, Suite 220, Redwood City, California 94061 | ------------------------------------------------------------------------------ | ADAPT-PT FOR POST-TENSIONED BEAM/SLAB DESIGN | | Version 6.08 AMERICAN (ACI-318-99/UBC-1997) | | Tel: (650)306-2400, Fax: (650)364-4678 | | [email protected], www.AdaptSoft.com | ------------------------------------------------------------------------------ DATE AND TIME OF PROGRAM EXECUTION: Sep 29,2000 At Time: 15:55 PROJECT FILE: MNL-INST P R O J E C T T I T L E: TWO SPAN T-BEAM FOR INITIAL VERIFICATION (MNL-INST) 1 - USER SPECIFIED G E N E R A L D E S I G N P A R A M E T E R S ============================================================================== CONCRETE: STRENGTH at 28 days, for BEAMS/SLABS ............. 28.00 N/mm^2 for COLUMNS ................. 28.00 N/mm^2 MODULUS OF ELASTICITY for BEAMS/SLABS ............ 24870.00 N/mm^2 for COLUMNS ................ 24870.00 N/mm^2 CREEP factor for deflections for BEAMS/SLABS ..... 2.00 CONCRETE WEIGHT .................................. NORMAL TENSION STRESS limits (multiple of (f'c)1/2) At Top .......................................... .500 At Bottom ....................................... .500 COMPRESSION STRESS limits (multiple of (f'c)) At all locations ................................. .450 REINFORCEMENT: YIELD Strength ................................... 460.00 N/mm^2 Minimum Cover at TOP ............................. 15.00 mm Minimum Cover at BOTTOM .......................... 15.00 mm POST-TENSIONING: SYSTEM ........................................... UNBONDED Ultimate strength of strand ...................... 1860.00 N/mm^2 Average effective stress in strand (final) ....... 1200.00 N/mm^2 Strand area....................................... 99.000 mm^2 Min CGS of tendon from TOP........................ 25.00 mm Min CGS of tendon from BOTTOM for INTERIOR spans.. 25.00 mm Min CGS of tendon from BOTTOM for EXTERIOR spans.. 25.00 mm Min average precompression ....................... .85 N/mm^2 Max spacing between strands (factor of slab depth) 8.00 Tendon profile type and support widths............ (see section 9) ANALYSIS OPTIONS USED: Structural system ................................ BEAM Moment of Inertia over support is ................ NOT INCREASED Moments REDUCED to face of support ............... YES Limited plastification allowed(moments redistributed) NO Effective flange width consideration ............. NO

3 - 20


2 - I N P U T G E O M E T R Y ============================================================================== 2.1.1 PRINCIPAL SPAN DATA OF UNIFORM SPANS ------------------------------------------------------------------------------ S F| | | TOP |BOTTOM/MIDDLE| | P O| | | FLANGE | FLANGE | REF | MULTIPLIER A R| LENGTH| WIDTH DEPTH| width thick.| width thick.|HEIGHT| left right N M| m | mm mm | mm mm | mm mm | mm | -1-----3----4-------5-------6-------7------8------9------10----11-----12----13- 1 2 20.00 460 915 2286 155 915 .50 .50 2 2 20.00 460 915 2286 155 915 .50 .50 ------------------------------------------------------------------------------ LEGEND: 1 - SPAN 3 - FORM C = Cantilever 1 = Rectangular section 2 = T or Inverted L section 11 - Top surface to reference line; positive reference line 2.2 - S U P P O R T W I D T H A N D C O L U M N D A T A SUPPORT <------- LOWER COLUMN ------> <------ UPPER COLUMN ------> WIDTH LENGTH B(DIA) D CBC* LENGTH B(DIA) D CBC* JOINT mm m mm mm m mm mm --1-------2---------3-------4-------5-----6---------7-------8-------9----10--- 1 915 .00 0 0 (1) .00 0 0 (1) 2 915 .00 0 0 (1) .00 0 0 (1) 3 915 .00 0 0 (1) .00 0 0 (1) *THE COLUMN BOUNDARY CONDITION CODES (CBC) Fixed at both ends ...(STANDARD) ............................. = 1 3 - I N P U T A P P L I E D L O A D I N G ============================================================================== <---CLASS---> <--------------TYPE-------------------> D = DEAD LOAD U = UNIFORM P = PARTIAL UNIFORM L = LIVE LOAD C = CONCENTRATED M = APPLIED MOMENT Li= LINE LOAD SW= SELF WEIGHT Computed from geometry input and treated as dead loading 3.1 - LOADING AS APPEARS IN USER`S INPUT SCREEN PRIOR TO PROCESSING ============================================================================== UNIFORM (kN/m^2), ( CON. or PART. ) ( M O M E N T ) SPAN CLASS TYPE LINE(kN/m) ( kN@m or m-m ) ( kN-m @ m ) -1-----2------3---------4------------5-------6-----------7-------8------------ 1 L Li 22.100 .00 20.00 1 D Li 23.880 .00 20.00 2 L Li 22.100 .00 20.00 2 D Li 23.880 .00 20.00 NOTE: LIVE LOADING is SKIPPED with a skip factor of 1.00

3 - 21


4 - C A L C U L A T E D S E C T I O N P R O P E R T I E S ============================================================================== 4.2 - Computed Section Properties for Segments of Nonprismatic Spans ------------------------------------------------------------------------------ Section properties are listed for all segments of each span A= cross-sectional geometry Yt= centroidal distance to top fiber I= gross moment of inertia Yb= centroidal distance to bottom fiber SPAN AREA I Yb Yt (SEGMENT) mm^2 mm^4 mm mm ---------------2----------------3---------------4-------------5----- SPAN 1 1 703930.00 .5437E+11 610.29 304.71 SPAN 2 1 703930.00 .5437E+11 610.29 304.71 9 - SELECTED POST-TENSIONING FORCES AND TENDON PROFILES ============================================================================== 9.1 PROFILE TYPES AND PARAMETERS LEGEND: For Span: 1 = reversed parabola 2 = simple parabola with straight portion over support 9.2 T E N D O N P R O F I L E TYPE X1/L X2/L X3/L A/L ----------1--------2----------3----------4----------5------ 1 1 .000 .500 .100 .000 2 1 .100 .500 .000 .000 9.3 - SELECTED POST-TENSIONING FORCES AND TENDON DRAPE ============================================================================== <-------- SELECTED VALUES --------> <- CALCULATED VALUES -> FORCE <- DISTANCE OF CGS (mm) -> P/A Wbal SPAN (kN/-) Left Center Right (N/mm^2) (kN/-) --1----------2---------3--------4--------5-----------6----------7--------- 1 2391.000 610.29 25.00 890.00 3.40 34.676 2 2391.000 890.00 25.00 610.29 3.40 34.676 11 - M I L D S T E E L ============================================================================== REINFORCEMENT based on NO REDISTRIBUTION of factored moments ------------------------------------------------------------------------------ 11.2.1 S T E E L A T M I D - S P A N T O P B O T T O M As DIFFERENT REBAR CRITERIA As DIFFERENT REBAR CRITERIA SPAN (mm^2) <---ULT-----MIN--D+.25L-> (mm^2) <---ULT-----MIN--D+.25L-> --1------2---------3-------4-------5-----------6---------7-------8-------9---- 1 0 ( 0 0 0) 0 ( 0 0 0) 2 0 ( 0 0 0) 0 ( 0 0 0)

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11.3.1 S T E E L A T S U P P O R T S T O P B O T T O M As DIFFERENT REBAR CRITERIA As DIFFERENT REBAR CRITERIA JOINT (mm^2) <---ULT-----MIN--D+.25L-> (mm^2) <---ULT-----MIN--D+.25L-> --1------2---------3-------4-------5-----------6---------7-------8-------9---- 1 0 ( 0 0 0) 1123 ( 923 1123 0) 2 1815 ( 1815 1693 0) 103 ( 103 0 0) 3 0 ( 0 0 0) 1123 ( 923 1123 0) 11.2.2 & 11.3.2 SELECTION OF REBAR ------------------------------------------------------ SPAN ID LOCATION NUM BAR LENGTH [mm] AREA [mm^2] --1----2-----3------4----5-------6---------7---------- 1 1 T 4 # 25 x 10600 2040 1 2 B 3 # 25 x 40600 1530 ------------------------------------------------------ Notes: Bar location - T = Top, B = Bottom. NUM - Number of bars. Refer to tables 11.5.1,11.5.2 and PTsum graphical display for positioning of bars. 14 - I N I T I A L CONDITION STRESS CHECK & REINFORCEMENT REQUIREMENTS ============================================================================== 14.1 Parameters specified as input for initial stress checks: Tensile stresses divided by (f`c)^1/2 Concrete f`c (initial/final) .75 Top fiber ........ .25 PT force (initial/final) ... 1.15 Bottom fiber ........ .25 Dead loading (initial/final) 1.00 Live loading (initial/final) .00 Compression as ratio of f`c .... .60 Note: Reinforcement reported in this data block is in addition to that reported in data block 11 for minimum and strength reinforcement required by code. 14.2.1 NO added MILD REINFORCEMENT is required for G R O U P 1* 14.2.2 SELECTION OF REBAR G R O U P 2* (REFER TO 14.2.3 FOR POSITION) <------- TOP STEEL --------> <------ BOTTOM STEEL ------> JOINT (mm^2) <-- SELECTION --> (mm^2) <-- SELECTION --> --1---------2--------3---4------5-----------------6--------7---8------9------- 1 0 0 2 0 1534 3 #25 x 6600 mm 3 0 0 14.3 Compressive stresses COMPRESSIVE stresses are within allowable limit ( .60 * f`ci ) MAXIMUM stress.............................. = .44 * f`ci (f`ci = initial concrete strength)

FIGURE 3.2.4-2

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3.2.5 VERIFICATION

The purpose of this section is to verify the results of the Initial Stresses Post-processor. Thetwo-span T-beam from Section 3.2.4 will be used. The following refers to data block 14,Initial Condition Stress Check & Reinforcement Requirements.

Data Block 14.1 - Parameters Specified As Input For Initial Stress Checks

The left column reflects information input by the user in both ADAPT-PT and in thepost-processor dialog box. The user has indicated that concrete strength at time ofstressing, f’ci, is 75% of the final strength, f’c. The post-tensioning force and deadloading are 115% and 100% of their values from the ADAPT-PT run, respectively.There is no live loading so the ratio is shown as zero.

In this example, the dead loading is due only to the weight of the beam. If there hadbeen a superimposed dead load that was not to be included during the initial stresscheck, the user would have input the dead load ratio as:

(Selfweight)/(Selfweight + Superimposed dead load)

The right column shows the tensile stress limits in terms of multiples of (f’c)1/2 . Thelast entry in the column gives the limit for compression stresses in terms of f’c. In thisexample, the tensile stress limit is 0.25 (f’ci)1/2, the compressive stress limit is 0.6 f’ci.

Data Block 14.2 – Additional Mild Reinforcement Required

In this example, additional steel is only required at the bottom of the second support.The following computations verify that the calculated area is correct. The results arereferenced to the Results Report, i.e. the notation ADAPT B4.2, C3 refers to column3 of block 4.2. Note that since these values are rounded off to the second decimalplace, there will be small discrepancies between these hand calculations and theADAPT-PT results.

Stresses due to initial conditions are recorded in the file INSTRS.DAT. The maxi-mum tensile stress are at X/L = 0.95 in span 1 and X/L = 0.05 in span 2. Stresses arecalculated as:

f = (+ M(combined)/S) - P/A

Where,

Sb = I/Yb = 5.437 x 1010 mm4 / 610.29 mm (ADAPT B4.2, C3, C4)= 8.908 x 107 mm3

St = I/Yt = 5.437 x 1010 mm4 / 304.71 mm (ADAPT B4.2, C3, C5)= 1.7843 x 108 mm3

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P/A = 1.15 * 3.40 N/mm2 = 3.91 N/mm2 (ADAPT B9.3, C6)

Moments are stored in the file MOMENTS.DAT. Evaluating the combination of1.00DL + 1.15PT at X/L=0.05 gives:

M(combined,X/L=0.05) = 1.00*(-906.7) + 1.15*(1450)= 760.8 kN-m

fb = (760.8 x 106)/(8.908 x 107) - 3.91= 4.63 N/mm2 (T) (ADAPT 4.63, INSTRS.DAT)

ft = (-760.8 x 106)/(1.784 x 108) - 3.91= -8.17 N/mm2

= 8.17 N/mm2 (C) (ADAPT -8.17, INSTRS.DAT)

The allowable tensile stresses are calculated as:

f’ci = 0.75 f’c = 0.75 * 28 N/mm2 = 21 N/mm2

fallowable, (T) = 0.25(f’ci)1/2 = 0.25 * 211/2

= 1.15 N/mm2 (tension)

Since the tensile stress fb(4.63 N/mm2 ) is greater than the allowable value (1.15 N/mm2), nonprestressed reinforcement needs to be provided. Mild reinforcement isprovided for the tension force (T) on the concrete section using the following relation-ship from ACI-318:

As = T/(0.5*fy)T = tension forcefy = 460 N/mm2 (ADAPT B1)

The tensile force is found by assuming a linear stress distribution as shown in Fig.3.2.5-1:

h = 915 mmbw = 460 mm

X = [4.63/(4.63 + 8.17)]*915= 330.97 mm

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FIGURE 3.2.5-1

T = (330.97*460/2)*4.63/1000= 352450 N

Steel required for the initial conditions is recorded in the file INISTL.DAT.

As = 352450/(0.5*460)= 1532 mm2 (ADAPT 1534 mm2, INISTL.DAT)

Additional steel is the difference between the total required for initial stress condi-tions and that required for the ADAPT run as recorded in the file SELBAR.DAT.

At X/L = 0.05 in the second span:

As due to initial stress only = 1534 mm2 (INISTL.DAT)As, due to other considerations = 0 mm2 (SELBAR.DAT)

As, to be added = 1534 - 0 = 1534 mm2 (ADAPT 1534 mm, B14.2.2, C6)

Data Block 14.3 - Compressive Stresses

The initial compressive strength, f’ci, is the ratio of f’c specified in the post processordialog window. In this example:

f’ci = 0.75*f’c (ADAPT B14.1)= 0.75*28 = 21 N/mm2

Allowable stresses were as 0.60*f’ci. Therefore, the maximum allowable stress is:

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0.60*21 = 12.6 N/mm2

The maximum compressive stress, as shown in the file INSTRS.DAT, is 9.25 N/mm2

at X/L=.50

9.26/21 = 0.4409 (ADAPT 0.44, B14.3)

The maximum stress is thus reported as 0.44*f’ci:

0.44*f’ci = 0.44*21 = 9.24 N/mm2 (C)

The small discrepancy is due to rounding.

3.2.6 SPECIFIC FEATURES OF VERSIONS OTHER THAN ACI

Calculation of initial stresses and additional required steel are carried out in the same mannerfor all the codes. The verification in the previous section applies to all of the codes availablein ADAPT-PT.

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3.3 LATERAL ANALYSIS

3.3.1 BACKGROUND

In this document, lateral forces refers to the forces and effects that are generated in aslab/beam frame due to wind or earthquake. The forces and moments due to thelateral loading are additive to those due to gravity.

In high seismic or wind areas however, buildings are usually provided with membersthat are specifically designated to resist the lateral forces. These members are calledthe primary lateral load resisting members. Collectively, they make up the lateralforce resisting structural system of the building. The primary lateral load resistingsystem of a building must be designed for gravity and lateral forces. Common lateralload resisting systems are shear wall systems, braced frames, and moment frames.

Where relatively high lateral forces and possibly large horizontal displacements areanticipated, the integrity of the members which are not part of the primary lateral loadresisting system must be checked against the displacements of the building. Suchframes are not expected to contribute to the resistance of the lateral loads but areexpected to remain serviceable after the lateral load-inducing event. The UniformBuilding Code (UBC), for example, requires that all framing members which are notpart of the lateral force-resisting system be shown adequate for a combination ofgravity loads and induced moments due to a prescribed multiple of the displacementscaused by the code-required lateral forces.

Post-tensioned buildings that are not subjected to either high seismic or high windloadings typically do not have a separate lateral load resisting system. The slabs andbeams are designed to resist the wind or seismic forces in proportion to either theirtributary area or the area of façade they support.

The UBC requirements for the primary lateral force-resisting members are:

Mu = 0.75*(1.40Md + 1.70Ml + 1.70Mlat) + 1.00Msec (1)Mu = 0.90Md + 0.00Ml + 1.30Mlat

+ 1.00Msec (2)

Where,

Mu = Factored moment accounting for lateral effects;Md = moment due to dead loading;Ml = moment due to live loading;Msec = secondary moment due to prestressing; and,Mlat = moment due to wind loading. The coefficient is multiplied by 1.1 if

Mlat is due to earthquake.

The intent of the two UBC relationships is to cover the most adverse combinations ofdead, live and lateral loading to determine the factored moments that a given member

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should be designed to resist. Note that the factors 1.4, 1.7, etc, are quoted for illustra-tion only, they may be different in other codes. The designer must determine thegoverning factors using the applicable building code.

It should also be noted that in the design of prestressed members subject to wind orearthquake loading, only the member’s strength performance is checked against thecombinations of lateral actions and gravity loadings. Lateral loading is not consideredwhen doing the serviceability stress checks that are used to determine the requiredprestressing forces. For this reason, the design for lateral loading is viewed as a post-processing operation in which the gravity design, and therefore the prestressing, isalready determined.

Percentage of Prestressing Available

When calculating the required mild reinforcement for the combined actions of gravityand lateral loading, all or part of the prestressing in the section may be consideredavailable. The percentage of prestressing to include in the strength analysis for thecombined actions is specified by the user. For wind loading, the common practice isto assume that 100% of the prestressing is effective. For earthquake loading in highseismic regions (Zone IV of UBC) a lesser value is recommended, in order to providea larger amount of mild reinforcement, thereby increasing ductility.

Two-way Slab Systems

In addition to the check for the total combined moment to be resisted by the frame,there is a second requirement for two-way systems. At any joint of a two-way system,ACI requires that a fraction of column moment be resisted by a narrow strip of slab(referred to as the a strip) immediately over the column. This is referred to as transferof unbalanced joint moment. The a strip extends 1.5 times the slab thickness, or thedrop thickness if there is one, on either side of the column as illustrated in Fig. 3.3.1-1.

The fraction of unbalanced moment to be transferred by the a strip at each joint iscalculated as:

γ = {1/(1 + (2/3)*[(c1+d)/(c2+d)]1/2}

Where,

c1 = size of rectangular or equivalent rectangular column, capital, orbracket measured in the direction of the span for which moments arebeing determined,

c2 = size of rectangular or equivalent rectangular column, capital, orbracket measured transverse to the direction of the span

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FIGURE 3.3.1-1

d = distance of compression fiber to center of tension

For two-way slab systems, the width of slab on either side of the column to be consid-ered as the making up the plane frame must also be determined. This is further dis-cussed at the end of this chapter.

3.3.2 ANALYSIS PROCEDURE

For slab/beam frames subjected to lateral forces, either wind or earthquake, thefollowing design procedure is commonly adopted:

1. Design the frame for gravity loading.

2. Combine the actions due to lateral loading with those from the gravity load-ing.

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3. Check the adequacy of each member for the combined actions. If necessary,add mild reinforcement to meet the requirements of the combined actions.

Figure 3.3.2-1 illustrates the loading and moments on a single span of a continuousframe. Figure 3.3.2-1(a) shows the dead and live loading, a post-tensioning tendon,and lateral loading.

The procedure used by ADAPT in analysis and design for lateral moments is asfollows:

1. The moments due to lateral loading (Mlat) at each end of a beam/slab span arecomputed using an independent frame analysis. For this example, thesemoments are shown in Fig. 3.3.2-1(e). Note that the lateral moments varylinearly between adjacent support centerlines. Often, these moments can

FIGURE 3.3.2-1

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2. Moments at 1/20th points due to dead loading are determined by ADAPT aspart of the gravity analysis. These are shown for a typical case in Fig. 3.3.2-1(b).

3. There are two considerations for live loading.

Live loading may be completely absent. Since the absence of live loadingmay lead to more severe conditions at some points, the factor for the liveloading is commonly zero in one of the moment combination equations.

When live loading is present, its arrangement on different spans should maxi-mize the moments at given points. A typical moment envelope is shown inFig. 3.3.2-1(c). The envelope lists the maximum positive and negative mo-ments at 1/20th points along each span due to different live load patterns.This type of envelope is generated whenever skipped live loading is specified.If live loading is skipped, each of the two load combination equations must beevaluated twice at any given point along the span, once with the maximumpositive live load moment and once with the maximum negative live loadmoment.

4. Since this is a strength evaluation of a prestressed member, secondary (hyper-static) moments due to post-tensioning must be included. Note that the sec-ondary moments also vary linearly from support to support. The combinationfactor commonly used for secondary moments is typically one since theparameters governing their magnitudes are well defined and are not subject tothe statistical scatter that applies to dead and live loading. Secondary mo-ments are calculated by ADAPT at 1/20th points along each span. For acomplete description of secondary moments and their evaluations, refer to thechapter on Theory in the Software Manual.

5. The lateral load moments are combined with the moments at 1/20th points dueto dead loading, live loading, and secondary moments derived from the gravitysolution using the two specified equations. Up to eight moment combinationsare evaluated for each of the 1/20th points along each span.

There are two relationships; if the lateral moments change sign, each relation-ship is evaluated once for the positive direction of the lateral moments, andonce for the reversed direction. If live load is skipped, each point is consideredwith both the maximum positive and maximum negative live load moment.The outcome of the combinations is listed as an envelope of factored momentsat 1/20th points as shown in Fig. 3.3.2-1(f).

change sign due to reversal in direction of the lateral loading. The user speci-fies whether a sign change for the lateral moments should be accounted forwhen calculating the critical load combinations.

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6. For the purposes of a summary report a set of six moment values are selectedfrom the list of factored moments generated at 1/20th points. These are: two atthe left support, two in the span, and two at the right support. At each loca-tion, the maximum and minimum moments are selected. For the left and rightsupports, the values are moments at the face-of-support, if the user has in-voked this option in inputdata. Otherwise, they are centerline values. For thein-span moments, the midspan values are selected. The values selected arelisted in data block 15.1 of the Results Report in columns 4 through 9. Thevalues of the moments at 1/20th points are recorded in the file LATBM.DAT.

7. The required mild reinforcement is calculated for each of the 1/20th points foreach span. The corresponding factored moment at each 1/20th point. Thereinforcement necessary for the lateral load case is listed at 1/20th points indata file LATSTL.DAT. In addition, this file includes the reinforcementneeded at the face-of-supports. This is a text file and can be viewed using aword processor. The maximum value of reinforcement for each of the threeregions left, center and right of each span are selected and reported in datablock 15 of the program output.

3.3.3 INPUT SCREENS

Figures 3.3.3-1 and 3.3.3-2 show the input screens for the Lateral Analysis.

The Settings tab shows the two underlying equations for the combination of moments,the combination coefficients are entered by the user. The bottom of the Settings tabshows the conditions that the user may impose for the combination of the momentsand the calculation of the required mild reinforcing. These conditions are:

� Whether the calculations should consider change of sign for the applied lateralmoments;

� What percentage of the post-tensioning available in the frame should beconsidered as contributing to the lateral load resistance; and,

� For two-way systems, the number of strands or the percentage of post-tension-ing which is available over the a strip. This information is used to determinethe rebar required for transfer of the unbalanced moments.

The Moments tab contains a table for entering the applied lateral moments at the endsof each span.

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FIGURE 3.3.3-1

FIGURE 3.3.3-2

3.3.4 DESCRIPTION OF PRINTOUT

A summary of the analysis and design for the combination of lateral and gravitymoments is saved in the file LATERAL.DAT. This file may be included in the Re-sults Report by checking the Lateral Analysis box on the Report Setup screen. TheLateral Analysis results are data block 15.

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3.3.4.1 Summary of Moments - file LATBM.DAT

Data Block 15.1

The first section of this block shows the combination coefficients entered bythe user. The applied moments are listed in columns 2 and 3. Representativemoments for each span, as illustrated in Fig. 3.3.2-1(f), are listed in columns 4through 9.

Data Block 15.2

This data block is only applicable to two-way systems, where a fraction of theunbalanced moment must be transferred through a strip of slab over thecolumn (the a strip). The coefficient γ, listed in column 2, is the fraction ofcolumn moment which must be resisted by the a strip. The actual value of themoment at the left and right of each joint is shown in columns 3 through 6.Both the maximum negative and maximum positive moments of the variouscombinations at each side of a joint are listed. These values are the productsof the respective unbalanced moments and the related γ value. The full unbal-anced moments to be resisted by the frame columns are shown in columns 7and 8. The unbalanced moment, Mc (=Mc1 + Mc2) is illustrated in Fig.3.3.4.1-1.

In some cases, the column moments printed in columns 7 and 8 do not appearto balance the corresponding joint moments. This is because the joint mo-ments are selected from the maxima occurring over a length of span (1/10)from each joint whereas the unbalanced moment refers strictly to the momentnecessary to statically balance the moments at the face-of-column and slab/beam. The influence of shear at the face-of-support on the column moment isdisregarded.

Column 9 of this data block indicates the amount of post-tensioning the userhas specified as being available within the “a” strip. This is used in thecalculation of additional rebar required at that location.

Data Block 15.3

This is the legend for the mild steel reinforcement printout.

Data Blocks 15.4, 15.5

This is a summary of the calculated and governing rebar along with the se-lected bar size, quantity, and length. Columns 2 and 6 of data blocks 15.4 and15.5 reflect the total mild steel reinforcement calculated to meet all lateralrequirements. These values do not reflect the gravity load analysis however.

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FIGURE 3.3.4.1-1

The user must compare these results with the gravity load analysis to deter-mine the governing condition.

3.3.4.2 Summary of Moments - file LATBM.DAT

The file LATBM.DAT contains the factors used for moment combinations andthe moments at 1/20th points along each span. This file also includes theapplied lateral moment computed for each point. Listings of the dead, live andsecondary moments are given in the data file MOMENTS.DAT which isgenerated during the gravity load analysis.

3.3.4.3 Summary of Mild Reinforcement - file LATSTL.DAT

This file lists the mild reinforcement requirements for the critical lateral andgravity moments listed in data blocks 15.1 and 15.2. In the absence of agraphical display of bar along the length of the spans, it is strongly recom-

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mended to consult this file for a clear indication of the amount and location ofthe bars.

3.3.5 EXAMPLES

This section contains two examples of the Lateral Analysis post-processor. They arebased on two of the designs given in Chapter 5 of the Software Manual.

EXAMPLE 1 - TWO-WAY EQUIVALENT FRAME ANALYZED FOR WINDLOADING

The three span two-way slab, MNL5-2M, is assumed to be subjected to a wind load-ing that causes the lateral moment distribution in the scale shown below.

FIGURE 3.3.5-1

An exerpt of the results of the gravity design along with the lateral analysis are listedin the verification part of this section.

EXAMPLE 2 - T-BEAM ANALYZED FOR EARTHQUAKE LOADING

The three span beam shown below is designed for gravity and lateral loading. It isassumed that the response of the structure to a given earthquake loading has resultedin the additional beam moments shown.

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FIGURE 3.3.5-2

The results of the ADAPT analysis for this case are given in the following excerptfrom the printout:

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------------------------------------------------------------------------------ | ADAPT CORPORATION | | STRUCTURAL CONCRETE SOFTWARE SYSTEM | | 1733 Woodside Road, Suite 220, Redwood City, California 94061 | ------------------------------------------------------------------------------ | ADAPT-PT FOR POST-TENSIONED BEAM/SLAB DESIGN | | Version 6.08 AMERICAN (ACI-318-99/UBC-1997) | | Tel: (650)306-2400, Fax: (650)364-4678 | | [email protected], www.AdaptSoft.com | ------------------------------------------------------------------------------ DATE AND TIME OF PROGRAM EXECUTION: Sep 27,2000 At Time: 15:28 PROJECT FILE: Mnl5_3_L P R O J E C T T I T L E: T-BEAM EXAMPLE FOR ADAPT POST TENSIONING SOFTWARE 1 - USER SPECIFIED G E N E R A L D E S I G N P A R A M E T E R S ============================================================================== CONCRETE: STRENGTH at 28 days, for BEAMS/SLABS ............. 4000.00 psi for COLUMNS ................. 4000.00 psi MODULUS OF ELASTICITY for BEAMS/SLABS ............ 3604.00 ksi for COLUMNS ................ 3604.00 ksi CREEP factor for deflections for BEAMS/SLABS ..... 2.00 CONCRETE WEIGHT .................................. NORMAL TENSION STRESS limits (multiple of (f'c)1/2) At Top .......................................... 9.000 At Bottom ....................................... 9.000 COMPRESSION STRESS limits (multiple of (f'c)) At all locations ................................. .450 REINFORCEMENT: YIELD Strength ................................... 60.00 ksi Minimum Cover at TOP ............................. 2.00 in Minimum Cover at BOTTOM .......................... 3.00 in POST-TENSIONING: SYSTEM ........................................... UNBONDED Ultimate strength of strand ...................... 270.00 ksi Average effective stress in strand (final) ....... 175.00 ksi Strand area....................................... .153 in^2 Min CGS of tendon from TOP........................ 2.25 in Min CGS of tendon from BOTTOM for INTERIOR spans.. 3.25 in Min CGS of tendon from BOTTOM for EXTERIOR spans.. 3.25 in Min average precompression ....................... 200.00 psi Max spacing between strands (factor of slab depth) 8.00 Tendon profile type and support widths............ (see section 9) ANALYSIS OPTIONS USED: Structural system ................................ ONE-WAY Moment of Inertia over support is ................ NOT INCREASED Moments REDUCED to face of support ............... YES Limited plastification allowed(moments redistributed) NO Effective flange width consideration ............. NO

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2 - I N P U T G E O M E T R Y ============================================================================== 2.1.1 PRINCIPAL SPAN DATA OF UNIFORM SPANS ------------------------------------------------------------------------------ S F| | | TOP |BOTTOM/MIDDLE| | P O| | | FLANGE | FLANGE | REF | MULTIPLIER A R| LENGTH| WIDTH DEPTH| width thick.| width thick.|HEIGHT| left right N M| ft | in in | in in | in in | in | -1-----3----4-------5-------6-------7------8------9------10----11-----12----13- 1 2 64.00 18.00 34.00 98.00 5.00 34.00 .50 .50 2 2 55.00 18.00 34.00 98.00 5.00 34.00 .50 .50 3 2 17.00 18.00 34.00 98.00 5.00 34.00 .50 .50 ------------------------------------------------------------------------------ LEGEND: 1 - SPAN 3 - FORM C = Cantilever 2 = T or Inverted L section 11 - Top surface to reference line; above reference line positive 2.2 - S U P P O R T W I D T H A N D C O L U M N D A T A SUPPORT <------- LOWER COLUMN ------> <------ UPPER COLUMN ------> WIDTH LENGTH B(DIA) D CBC* LENGTH B(DIA) D CBC* JOINT in ft in in ft in in --1-------2---------3-------4-------5-----6---------7-------8-------9----10--- 1 14.00 10.00 14.00 14.00 (3) .00 .00 .00 (1) 2 18.00 10.00 18.00 18.00 (1) .00 .00 .00 (1) 3 18.00 10.00 18.00 18.00 (1) .00 .00 .00 (1) 4 14.00 10.00 14.00 14.00 (3) .00 .00 .00 (1) *THE COLUMN BOUNDARY CONDITION CODES (CBC) Fixed at both ends ...(STANDARD) ............................. = 1 Fixed at near end, hinged at far end ......................... = 3 3 - I N P U T A P P L I E D L O A D I N G ============================================================================== <---CLASS---> <--------------TYPE-------------------> D = DEAD LOAD U = UNIFORM P = PARTIAL UNIFORM L = LIVE LOAD C = CONCENTRATED M = APPLIED MOMENT Li= LINE LOAD SW= SELF WEIGHT Computed from geometry input and treated as dead loading

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3.1 - LOADING AS APPEARS IN USER`S INPUT SCREEN PRIOR TO PROCESSING ============================================================================== UNIFORM (k/ft^2), ( CON. or PART. ) ( M O M E N T ) SPAN CLASS TYPE LINE(k/ft) ( k@ft or ft-ft ) ( k-ft @ ft ) -1-----2------3---------4------------5-------6-----------7-------8------------ 1 L Li .540 .00 64.00 1 D Li 1.900 .00 64.00 2 L Li .540 .00 55.00 2 D Li 1.900 .00 55.00 3 L Li .540 .00 17.00 3 D Li 1.900 .00 17.00 7 - M O M E N T S REDUCED TO FACE-OF-SUPPORT ============================================================================== 7.1 R E D U C E D DEAD LOAD MOMENTS (k-ft) SPAN <- left* -> <- midspan -> <- right* -> --1---------------2-------------3-------------4------------------------------- 1 -60.69 527.75 -747.42 2 -671.00 210.75 -267.08 3 -241.67 -62.42 2.90 Note: * = face-of-support 7.2 R E D U C E D LIVE LOAD MOMENTS (k-ft) <----- left* ------> <---- midspan ----> <----- right* -----> SPAN max min max min max min -1----------2----------3-----------4----------5-----------6----------7----- 1 -17.25 -17.25 150.00 150.00 -212.42 -212.42 2 -190.75 -190.75 59.89 59.89 -75.90 -75.90 3 -68.69 -68.69 -17.74 -17.74 .82 .82 Note: * = face-of-support 8 - SUM OF DEAD AND LIVE MOMENTS (k-ft) ============================================================================== Maxima of dead load and live load span moments combined for serviceability checks ( 1.00DL + 1.00LL ) <----- left* ------> <---- midspan ----> <----- right* -----> SPAN max min max min max min -1----------2----------3-----------4----------5-----------6----------7----- 1 -77.94 -77.94 677.75 677.75 -959.83 -959.83 2 -861.75 -861.75 270.64 270.64 -342.98 -342.98 3 -310.36 -310.36 -80.16 -80.16 3.72 3.72 Note: * = face-of-support

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9 - SELECTED POST-TENSIONING FORCES AND TENDON PROFILES ============================================================================== 9.1 PROFILE TYPES AND PARAMETERS LEGEND: 2 = simple parabola with straight portion over support 9.2 T E N D O N P R O F I L E TYPE X1/L X2/L X3/L A/L ----------1--------2----------3----------4----------5------ 1 2 .031 .500 .031 .000 2 2 .036 .500 .000 .000 3 2 .000 .500 .059 .000 9.3 - SELECTED POST-TENSIONING FORCES AND TENDON DRAPE ============================================================================== Tendon editing mode selected: FORCE SELECTION <-------- SELECTED VALUES --------> <- CALCULATED VALUES -> FORCE <- DISTANCE OF CGS (in) -> P/A Wbal SPAN (k/-) Left Center Right (psi) (k/-) --1----------2---------3--------4--------5-----------6----------7--------- 1 373.000 23.00 3.25 31.00 368.58 1.537 2 208.000 31.00 3.25 31.00 205.53 1.321 3 208.000 31.00 22.00 23.00 205.53 2.431 9.7 POST-TENSIONING B A L A N C E D M O M E N T S, SHEARS & REACTIONS <--REACTIONS (k )--> <-- COLUMN MOMENTS (k-ft) --> -joint------------2-----------------Lower columns-----Upper columns----- 1 4.034 60.317 .000 2 -7.011 -62.475 .000 3 -1.278 -21.600 .000 4 4.255 1.668 .000 10 - F A C T O R E D M O M E N T S & R E A C T I O N S ============================================================================== Calculated as ( 1.40D + 1.70L + 1.00 secondary moment effects) 10.2 SECONDARY MOMENTS (k-ft) SPAN <-- left* --> <- midspan -> <-- right* --> -1-----------2----------------3----------------4-------- 1 62.67 189.42 315.50 2 253.75 174.17 94.50 3 67.47 34.50 .81 Note: * = face-of-support

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11 - M I L D S T E E L ============================================================================== SPECIFIC CRITERIA for ONE-WAY or BEAM SYSTEM - Dead + 25% of unreduced Live load capacity requirement Ratio of reduced to total Live loading .... 1.00 - Minimum steel ............................. 0.004A - Moment capacity > factored (design) moment REINFORCEMENT based on NO REDISTRIBUTION of factored moments ------------------------------------------------------------------------------ 11.1 TOTAL WEIGHT OF REBAR = 2274.2 lb AVERAGE = 2.0 psf 11.2.1 S T E E L A T M I D - S P A N T O P B O T T O M As DIFFERENT REBAR CRITERIA As DIFFERENT REBAR CRITERIA SPAN (in^2) <---ULT-----MIN--D+.25L-> (in^2) <---ULT-----MIN--D+.25L-> --1------2---------3-------4-------5-----------6---------7-------8-------9---- 1 .00 ( .00 .00 .00) 3.98 ( 1.00 1.64 3.98) 2 .00 ( .00 .00 .00) 1.64 ( .00 1.64 1.58) 3 .00 ( .00 .00 .00) .00 ( .00 .00 .00) 11.3.1 S T E E L A T S U P P O R T S T O P B O T T O M As DIFFERENT REBAR CRITERIA As DIFFERENT REBAR CRITERIA JOINT (in^2) <---ULT-----MIN--D+.25L-> (in^2) <---ULT-----MIN--D+.25L-> --1------2---------3-------4-------5-----------6---------7-------8-------9---- 1 2.41 ( .00 2.41 .41) .00 ( .00 .00 .00) 2 5.52 ( 2.34 2.41 5.52) .00 ( .00 .00 .00) 3 2.41 ( .00 2.41 1.86) .00 ( .00 .00 .00) 4 .00 ( .00 .00 .00) 1.64 ( .00 1.64 .02) ------------------------------------------------------------------------------

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ADAPT - ST RUCTU RAL CO NCRETE SO FT W AR E SYS TEMA DA PT-PT V ersion 6 .08 Date : 9/2 9/00 Tim e: 8:07 :0 4 A M Fil e: M nl5 _3_L

1- PROJECT TITL E ADAPT PT M anu al1 .1 D ESIGN S TRIP T-BEAM E XAMP LE F OR ADAPT POST TENS IO NIN G S OFT W ARE

2 - MEM BER E LEV ATIO N [ft] 64 .00 5 5.0 0 17 .0 0

3 - TOP R EBAR




3 .4 ADAPT se lected 3 14 #4 X34 '6 "1 7# 4X1 8'0"

4 1 4#4 X1 7'0"2 6# 4X5 '6 "

7 7# 4X3 1'6"

8 6# 4X2 3'0"

4 - TENDON PROFILE

4 .2 D atum L ine4 .3 C GS Distance [in]4 .5 F orce

23 .0 0 3 .25 3 1. 00[ 37 3 kip s]

3 1. 00 3. 25 31 .0 0[2 08 kips]

3 1.0 0 2 2. 00 23 .0 0[20 8 kips]

5 - BOTTOM R EBAR5 .1 U ser se lected



5 .4 ADAPT se lected 5 3# 8X5 3'6"

6 3# 8X4 7'0"

9 2 #8 X3 8'0"

1 0 1 #8 X3 2'6"

11 3# 8X 6'6"

6 - REQUIRED & PROVIDED BARS

6 .1 T op Bars

[ in2]

req uired p ro vide d

6 .2 Bottom Bars

max

max

0 .0

2 .8

5 .6

2 .4

4 .8

5 .52

3 .98

4.9 1

1.6 4

2 .41

1 .64

7 - SHEAR STIRRU PS7 .1 ADAPT se lected . Bar Size # 6 Le gs: 2 Spa cing [in]

- 2 4 - 24 - 24 - 24 - 24 -

7 .2 U ser- sele cted Bar Size # L egs:

7 .3 R eq uired a rea

[in2/ft]

0 .00 00 .01 80 .03 6

0 .05 40 .07 2

.07 . 07 0

8 - LEGEND Stressing End Dead En d

9 - DESIGN PARAMETERS9 .1 Co de : AC I f'c = 4 ksi fy = 60 ksi ( lon g itud in al ) fy = 6 0 ksi (sh e ar ) fpu = 27 0 k si

9 .2 R eb ar Cove r: T op = 2 in B o ttom = 3 in Rebar T able: ASTM - US C ustom ary ba rs (Non-re distr ibu ted Moments)

9 .3 S tre ssin g: fp j = .8 fpu

9 .4 S tra nd Area = .1 5 3 in2

10 - D ESIGNER'S NOTES

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15 - REINFORCEMENT DUE TO MOMENTS FROM LATERAL FORCES ============================================================================== o Lateral moments are considered with positive and reversed directions o Percentage of post-tensioning considered in resisting lateral moments= 25 % o Factored moments calculated are the larger from the followings equations i ) Mu = (1.05Md + 1.28Ml + 1.00Msec + 1.40Mlat) ii ) Mu = ( .90Md + .00Ml + 1.00Msec + 1.43Mlat) Where, Md = dead load moments; Ml = live load moments; Msec = secondary moments; and Mlat = lateral moments. 15.1 INPUTTED LATERAL MOMENTS AND THE RESULTING COMBINED MOMENTS k-ft <- I N P U T -> <------- CALCULATED FACTORED SPAN MOMENTS Mu ------> LATERAL MOMENTS LEFT MID-SPAN RIGHT span left right neg------pos neg------pos neg------pos -1------2--------3----------4--------5---------6--------7---------8--------9-- 1 225.00 -225.00 -332.39 323.93 .00 935.48 -1048.83 .00 2 250.00 -250.00 -1035.38 .00 .00 472.08 -623.55 201.87 3 350.00 -350.00 -720.96 306.31 -53.74 .00 -462.73 469.57 Note: Moments listed under 4,5,8,9 are reduced to face-of-support, if applicable. For distribution of moments see file LATBM.DAT 15.2 COLUMN MOMENTS MAX COLUMN MU JNT neg------pos -1-----2----------3--------4---------5--------6---------7--------8---------9-- 1 -332.39 323.93 2 -654.86 694.36 3 -808.24 799.94 4 -469.57 462.73 Columns 7 and 8 are the sum of top and bottom column moments 15.3 LEGENDS AND NOTES FOR MILD STEEL Columns 2 and the like in following block list total rebar due to lateral forces. These are not in addition to other considerations reported in preceding blocks. For details of rebar reinforcement refer to file LATSTL.DAT 15.4 NO added MILD REINFORCEMENT is required at MID-SPAN 15.5 SELECTION OF REBAR AT S U P P O R T S <------ T O P S T E E L ----> <----- B O T T O M S T E E L ---> JNT (in^2) Ult SELECTION (in^2) Ult SELECTION -1-----2----3----4-----------5-------------6----7------8-----------9---------- 1 1.10( 1.10 ) 4 # 5 x 5'-6" 5.63( 5.63 ) 8 # 8 x 66'-0" 2 6.56( 6.56 ) 22 # 5 x 31'-6" 3 4.46( 4.46 ) 15 # 5 x 21'-6" 2.97( 2.97 ) 4 # 8 x 64'-0" 4 2.62( 2.62 ) 9 # 5 x 10'-0" 3.05( 3.05 ) 4 # 8 x 10'-0" For exact location of the bars refer to the file LATSTL.DAT.

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ADAPT STRUCTURAL CONCRETE SOFTWARE SYSTEM DATE: Sep 27,2000 TIME: 14:05 Data ID: Mnl5_3_L Output File ID: LATSTL.DAT ============================================================================== SUMMARY OF REBAR REQUIRED AT 1/20TH POINTS DUE TO ULTIMATE LATERAL MOMENTS Note: This is NOT in addition to rebar from other considerations Note: for LEFT CANTILEVER (if any) X/L= 0.00 is at tip of cantilever, and X/L= 1.00 is at first support SPAN = 1 LENGTH = 64.00 feet ; CLEAR from .58 to 63.25 ft X/L X <--Reinforcement (in^2)--> ft TOP BOTTOM ------------------------------------------------------------------------------ .00 .00 .05 3.20 .00 2.42 .10 6.40 .00 3.39 .15 9.60 .00 4.18 .20 12.80 .00 4.81 .25 16.00 .00 5.26 .30 19.20 .00 5.53 .35 22.40 .00 5.63 .40 25.60 .00 5.55 .45 28.80 .00 5.29 .50 32.00 .00 4.85 .55 35.20 .00 4.73 .60 38.40 .00 4.44 .65 41.60 .00 3.98 .70 44.80 .00 3.37 .75 48.00 .00 2.60 .80 51.20 .00 1.83 .85 54.40 .53 1.37 .90 57.60 2.33 .82 .95 60.80 4.43 .19 1.00 64.00 SPAN = 2 LENGTH = 55.00 feet ; CLEAR from .75 to 54.25 ft X/L X <--Reinforcement (in^2)--> ft TOP BOTTOM ------------------------------------------------------------------------------ .00 .00 .05 2.75 4.89 .19 .10 5.50 3.38 .43 .15 8.25 2.05 .63 .20 11.00 .88 .77 .25 13.75 .08 1.55 .30 16.50 .00 1.71 .35 19.25 .00 2.04 .40 22.00 .00 2.26 .45 24.75 .00 2.34 .50 27.50 .00 2.30 .55 30.25 .00 2.66 .60 33.00 .00 2.88 .65 35.75 .00 2.97 .70 38.50 .00 2.94 .75 41.25 .00 2.77 .80 44.00 .00 2.48 .85 46.75 .35 2.08 .90 49.50 1.35 1.86 .95 52.25 2.61 1.57 1.00 55.00

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SPAN = 3 LENGTH = 17.00 feet ; CLEAR from .75 to 16.42 ft X/L X <--Reinforcement (in^2)--> ft TOP BOTTOM ------------------------------------------------------------------------------ .00 .00 .05 .85 4.39 2.06 .10 1.70 3.78 1.76 .15 2.55 3.19 1.47 .20 3.40 2.62 1.18 .25 4.25 2.07 .89 .30 5.10 1.54 .59 .35 5.95 1.03 .29 .40 6.80 .53 .00 .45 7.65 .05 .00 .50 8.50 .00 .00 .55 9.35 .00 .00 .60 10.20 .09 .23 .65 11.05 .37 .64 .70 11.90 .67 1.04 .75 12.75 .98 1.43 .80 13.60 1.33 1.82 .85 14.45 1.70 2.20 .90 15.30 2.09 2.58 .95 16.15 2.49 2.94 1.00 17.00 REBAR REQUIRED AT FACES OF SUPPORTS ============================================================================== SPAN = 1 LENGTH = 64.00 feet ; CLEAR from .58 to 63.25 ft X/L X <--Reinforcement (in^2)--> ft TOP BOTTOM ------------------------------------------------------------------------------ face of support at left .01 .58 1.10 1.63 face of support at right .99 63.25 6.56 .00 SPAN = 2 LENGTH = 55.00 feet ; CLEAR from .75 to 54.25 ft X/L X <--Reinforcement (in^2)--> ft TOP BOTTOM ------------------------------------------------------------------------------ face of support at left .01 .75 6.42 .00 face of support at right .99 54.25 3.64 1.32 SPAN = 3 LENGTH = 17.00 feet ; CLEAR from .75 to 16.42 ft X/L X <--Reinforcement (in^2)--> ft TOP BOTTOM ------------------------------------------------------------------------------ face of support at left .04 .75 4.46 2.09 face of support at right .97 16.42 2.62 3.05

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ADAPT STRUCTURAL CONCRETE SOFTWARE SYSTEM DATE: Sep 27,2000 TIME: 14:05 Data ID: Mnl5_3_L Output File ID: LATBM.DAT ============================================================================== DISTRIBUTION OF LATERAL MOMENTS AT 1/20TH POINTS ALONG EACH SPAN TOGETHER WITH MAXIMA OF POSITIVE AND NEGATIVE FACTORED MOMENTS AT EACH POINT USING THE FOLLOWING TWO LOAD COMBINATION EXPRESSIONS : i ) Mu = (1.05Md + 1.28Ml + 1.00Msec + 1.40Mlat) ii ) Mu = ( .90Md + .00Ml + 1.00Msec + 1.43Mlat) Where, Md = dead load moments; Ml = live load moments; Msec = secondary moments; and Mlat = lateral moments. Units : ft and (k-ft) SPAN = 1 LENGTH = 64.00 feet (Net span from .58 to 63.25 ft ) Applied lateral moments Maxima of combined moments X/L X positive reversed largest smallest ---1-------2-------------3------------4---------------5-------------6----- .00 .00 225.00 -225.00 301.65 -381.00 .05 3.20 202.50 -202.50 441.43 -162.43 .10 6.40 180.00 -180.00 606.34 -.53 .15 9.60 157.50 -157.50 743.76 143.87 .20 12.80 135.00 -135.00 853.67 270.76 .25 16.00 112.50 -112.50 936.06 380.13 .30 19.20 90.00 -90.00 990.97 471.99 .35 22.40 67.50 -67.50 1018.35 546.35 .40 25.60 45.00 -45.00 1018.24 603.20 .45 28.80 22.50 -22.50 990.62 642.53 .50 32.00 .00 .00 935.48 664.35 .55 35.20 -22.50 22.50 915.85 604.31 .60 38.40 -45.00 45.00 868.70 526.76 .65 41.60 -67.50 67.50 794.05 431.70 .70 44.80 -90.00 90.00 691.89 319.13 .75 48.00 -112.50 112.50 562.23 189.06 .80 51.20 -135.00 135.00 427.57 27.06 .85 54.40 -157.50 157.50 326.82 -220.62 .90 57.60 -180.00 180.00 208.57 -495.80 .95 60.80 -202.50 202.50 72.79 -798.50 1.00 64.00 -225.00 225.00 -80.50 -1128.70 SPAN = 2 LENGTH = 55.00 feet (Net span from .75 to 54.25 ft ) Applied lateral moments Maxima of combined moments X/L X positive reversed largest smallest ---1-------2-------------3------------4---------------5-------------6----- .00 .00 250.00 -250.00 -30.29 -1105.33 .05 2.75 225.00 -225.00 67.31 -856.17 .10 5.50 200.00 -200.00 151.98 -627.34 .15 8.25 175.00 -175.00 223.73 -418.80 .20 11.00 150.00 -150.00 282.53 -230.59 .25 13.75 125.00 -125.00 328.41 -62.69 .30 16.50 100.00 -100.00 364.89 75.35 .35 19.25 75.00 -75.00 422.15 166.86 .40 22.00 50.00 -50.00 459.12 245.44 .45 24.75 25.00 -25.00 475.76 311.09 .50 27.50 .00 .00 472.08 363.81 .55 30.25 -25.00 25.00 518.09 332.09 .60 33.00 -50.00 50.00 543.79 287.45 .65 35.75 -75.00 75.00 549.17 229.86 .70 38.50 -100.00 100.00 534.24 159.35

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.75 41.25 -125.00 125.00 498.99 75.90 .80 44.00 -150.00 150.00 443.44 -20.46 .85 46.75 -175.00 175.00 370.73 -129.77 .90 49.50 -200.00 200.00 319.99 -288.62 .95 52.25 -225.00 225.00 256.32 -475.13 1.00 55.00 -250.00 250.00 179.72 -681.94 SPAN = 3 LENGTH = 17.00 feet (Net span from .75 to 16.42 ft ) Applied lateral moments Maxima of combined moments X/L X positive reversed largest smallest ---1-------2-------------3------------4---------------5-------------6----- .00 .00 350.00 -350.00 332.58 -794.13 .05 .85 315.00 -315.00 302.71 -711.35 .10 1.70 280.00 -280.00 271.61 -630.52 .15 2.55 245.00 -245.00 239.27 -551.63 .20 3.40 210.00 -210.00 205.70 -474.68 .25 4.25 175.00 -175.00 170.89 -399.68 .30 5.10 140.00 -140.00 134.86 -326.60 .35 5.95 105.00 -105.00 97.57 -255.48 .40 6.80 70.00 -70.00 59.06 -186.29 .45 7.65 35.00 -35.00 19.31 -119.05 .50 8.50 .00 .00 -21.67 -53.74 .55 9.35 -35.00 35.00 36.21 -88.38 .60 10.20 -70.00 70.00 92.85 -124.95 .65 11.05 -105.00 105.00 148.26 -163.47 .70 11.90 -140.00 140.00 202.43 -203.93 .75 12.75 -175.00 175.00 255.37 -246.33 .80 13.60 -210.00 210.00 307.07 -293.53 .85 14.45 -245.00 245.00 357.54 -343.16 .90 15.30 -280.00 280.00 406.77 -394.03 .95 16.15 -315.00 315.00 454.77 -446.13 1.00 17.00 -350.00 350.00 501.53 -499.47 SPAN = 1 LENGTH = 64.00 feet (Net span from .58 to 63.25 ft ) X/L X positive reversed largest smallest ---1-------2-------------3------------4---------------5-------------6----- .01 .58 220.90 -220.90 323.93 -332.39 .99 63.25 -219.73 219.73 -43.00 -1048.83 SPAN = 2 LENGTH = 55.00 feet (Net span from .75 to 54.25 ft ) X/L X positive reversed largest smallest ---1-------2-------------3------------4---------------5-------------6----- .01 .75 243.18 -243.18 -2.36 -1035.38 .99 54.25 -243.18 243.18 201.87 -623.55 SPAN = 3 LENGTH = 17.00 feet (Net span from .75 to 16.42 ft ) X/L X positive reversed largest smallest ---1-------2-------------3------------4---------------5-------------6----- .04 .75 319.12 -319.12 306.31 -720.96 .97 16.42 -325.98 325.98 469.57 -462.73

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3.3.6 VERIFICATION

The purpose of this section is to provide a procedure for verifying the results of theLateral Analysis. The results of Example 1, a two-way Equivalent Frame subjected towind loading (case MNL5-2M), are used.

FIGURE 3.3.6-1

Three files are generated in the calculation of steel required for lateral moment:LATERAL.DAT, LATBM.DAT and LATSTL.DAT. The gravity load moments areobtained from the file MOMENTS.DAT. The file LATBM.DAT is included belowfor reference.

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------------------------------------------------------------------------------ | ADAPT CORPORATION | | STRUCTURAL CONCRETE SOFTWARE SYSTEM | | 1733 Woodside Road, Suite 220, Redwood City, California 94061 | ------------------------------------------------------------------------------ | ADAPT-PT FOR POST-TENSIONED BEAM/SLAB DESIGN | | Version 6.08 AMERICAN (ACI-318-99/UBC-1997) | | Tel: (650)306-2400, Fax: (650)364-4678 | | [email protected], www.AdaptSoft.com | ------------------------------------------------------------------------------ DATE AND TIME OF PROGRAM EXECUTION: Sep 27,2000 At Time: 15:27 PROJECT FILE: Mnl5_2m_L P R O J E C T T I T L E: TWO-WAY EQUIVALENT FRAME SLAB EXAMPLE FOR ADAPT (SI) 1 - USER SPECIFIED G E N E R A L D E S I G N P A R A M E T E R S ============================================================================== CONCRETE: STRENGTH at 28 days, for BEAMS/SLABS ............. 28.00 N/mm^2 for COLUMNS ................. 28.00 N/mm^2 MODULUS OF ELASTICITY for BEAMS/SLABS ............ 24870.00 N/mm^2 for COLUMNS ................ 24870.00 N/mm^2 CREEP factor for deflections for BEAMS/SLABS ..... 2.00 CONCRETE WEIGHT .................................. NORMAL TENSION STRESS limits (multiple of (f'c)1/2) At Top .......................................... .500 At Bottom ....................................... .500 COMPRESSION STRESS limits (multiple of (f'c)) At all locations ................................. .450 REINFORCEMENT: YIELD Strength ................................... 460.00 N/mm^2 Minimum Cover at TOP ............................. 25.00 mm Minimum Cover at BOTTOM .......................... 25.00 mm POST-TENSIONING: SYSTEM ........................................... UNBONDED Ultimate strength of strand ...................... 1860.00 N/mm^2 Average effective stress in strand (final) ....... 1200.00 N/mm^2 Strand area....................................... 99.000 mm^2 Min CGS of tendon from TOP........................ 25.00 mm Min CGS of tendon from BOTTOM for INTERIOR spans.. 25.00 mm Min CGS of tendon from BOTTOM for EXTERIOR spans.. 25.00 mm Min average precompression ....................... .75 N/mm^2 Max spacing between strands (factor of slab depth) 8.00 Tendon profile type and support widths............ (see section 9) ANALYSIS OPTIONS USED: Structural system ....(using EQUIVALENT FRAME).... TWO-WAY Moments REDUCED to face of support ............... YES Limited plastification allowed(moments redistributed) NO

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2 - I N P U T G E O M E T R Y ============================================================================== 2.1.1 PRINCIPAL SPAN DATA OF UNIFORM SPANS ------------------------------------------------------------------------------ S F| | | TOP |BOTTOM/MIDDLE| | P O| | | FLANGE | FLANGE | REF | MULTIPLIER A R| LENGTH| WIDTH DEPTH| width thick.| width thick.|HEIGHT| left right N M| m | mm mm | mm mm | mm mm | mm | -1-----3----4-------5-------6-------7------8------9------10----11-----12----13- 1 1 5.75 1000 260 260 3.00 2.50 2 1 8.20 1000 260 260 3.00 2.50 3 1 6.75 1000 260 260 3.00 2.50 C 1 .90 1000 260 260 3.00 2.50 ------------------------------------------------------------------------------ LEGEND: 1 - SPAN 3 - FORM C = Cantilever 1 = Rectangular section 11 - Top surface to reference line 2.1.5 - D R O P C A P A N D D R O P P A N E L D A T A ============================================================================== CAPT CAPB CAPDL CAPDR DROPTL DROPTR DROPB DROPL DROPR JOINT mm mm mm mm mm mm mm mm mm --1------2-------3-------4-------5---------6-------7-------8-------9-------10- 1 0 0 0 0 0 0 0 0 0 2 460 1100 800 800 0 0 0 0 0 3 460 1100 800 800 0 0 0 0 0 4 0 0 0 0 0 0 0 0 0 ------------------------------------------------------------------------------ LEGEND: DROP CAP DIMENSIONS: CAPT = Total depth of cap CAPB = Transverse Width CAPDL = Extension left of joint CAPDR = Extension right of joint 2.2 - S U P P O R T W I D T H A N D C O L U M N D A T A SUPPORT <------- LOWER COLUMN ------> <------ UPPER COLUMN ------> WIDTH LENGTH B(DIA) D CBC* LENGTH B(DIA) D CBC* JOINT mm m mm mm m mm mm --1-------2---------3-------4-------5-----6---------7-------8-------9----10--- 1 200 3.00 5500 200 (2) .00 0 0 (1) 2 450 3.00 300 450 (1) .00 0 0 (1) 3 450 3.00 300 450 (1) .00 0 0 (1) 4 200 3.00 5500 200 (2) .00 0 0 (1) *THE COLUMN BOUNDARY CONDITION CODES (CBC) Fixed at both ends ...(STANDARD) ............................. = 1 Hinged at near end, fixed at far end ......................... = 2 3 - I N P U T A P P L I E D L O A D I N G ============================================================================== <---CLASS---> <--------------TYPE-------------------> D = DEAD LOAD U = UNIFORM P = PARTIAL UNIFORM L = LIVE LOAD C = CONCENTRATED M = APPLIED MOMENT Li= LINE LOAD SW= SELF WEIGHT Computed from geometry input and treated as dead loading

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3.1 - LOADING AS APPEARS IN USER`S INPUT SCREEN PRIOR TO PROCESSING ============================================================================== UNIFORM (kN/m^2), ( CON. or PART. ) ( M O M E N T ) SPAN CLASS TYPE LINE(kN/m) ( kN@m or m-m ) ( kN-m @ m ) -1-----2------3---------4------------5-------6-----------7-------8------------ 1 L U 6.400 1 D U 13.500 2 L U 5.500 2 D U 13.500 3 L U 6.000 3 D U 13.500 CANT L U 6.000 CANT D U 13.500 7 - M O M E N T S REDUCED TO FACE-OF-SUPPORT ============================================================================== 7.1 R E D U C E D DEAD LOAD MOMENTS (kNm) SPAN <- left* -> <- midspan -> <- right* -> --1---------------2-------------3-------------4------------------------------- 1 14.04 107.50 -337.00 2 -352.60 178.30 -405.70 3 -404.80 170.80 -11.96 CANT -23.76 ----- ----- * = face-of-support 7.2 R E D U C E D LIVE LOAD MOMENTS (kNm) <----- left* ------> <---- midspan ----> <----- right* -----> SPAN max min max min max min -1----------2----------3-----------4----------5-----------6----------7----- 1 6.91 6.91 58.16 58.16 -145.90 -145.90 2 -149.50 -149.50 67.97 67.97 -168.80 -168.80 3 -171.60 -171.60 80.21 80.21 -5.19 -5.19 CR -10.56 ----- ----- 9 - SELECTED POST-TENSIONING FORCES AND TENDON PROFILES ============================================================================== 9.3 - SELECTED POST-TENSIONING FORCES AND TENDON DRAPE ============================================================================== Tendon editing mode selected: FORCE SELECTION <-------- SELECTED VALUES --------> <- CALCULATED VALUES -> FORCE <- DISTANCE OF CGS (mm) -> P/A Wbal SPAN (kN/-) Left Center Right (N/mm^2) (kN/-) --1----------2---------3--------4--------5-----------6----------7--------- 1 1238.000 130.00 25.00 235.00 .87 9.985 2 1238.000 235.00 25.00 235.00 .87 6.539 3 1650.000 235.00 25.00 150.00 1.15 10.259 CANT 1650.000 150.00 130.00 1.15 14.815 Approximate weight of strand ........................... 214.9 Kg

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9.7 POST-TENSIONING B A L A N C E D M O M E N T S, SHEARS & REACTIONS <--REACTIONS (kN)--> <-- COLUMN MOMENTS (kNm ) --> -joint------------2-----------------Lower columns-----Upper columns----- 1 8.824 .000 .000 2 -8.854 -9.573 .000 3 -8.797 18.660 .000 4 8.827 .000 .000 10 - F A C T O R E D M O M E N T S & R E A C T I O N S ============================================================================== Calculated as ( 1.40D + 1.70L + 1.00 secondary moment effects) 10.2 SECONDARY MOMENTS (kNm) SPAN <-- left* --> <- midspan -> <-- right* --> -1-----------2----------------3----------------4-------- 1 .88 25.37 48.75 2 41.16 41.04 40.93 3 57.60 29.79 .88 Note: * = face-of-support 11 - M I L D S T E E L ============================================================================== REINFORCEMENT based on NO REDISTRIBUTION of factored moments ------------------------------------------------------------------------------ 11.2.1 S T E E L A T M I D - S P A N T O P B O T T O M As DIFFERENT REBAR CRITERIA As DIFFERENT REBAR CRITERIA SPAN (mm^2) <---ULT-----TENS--------> (mm^2) <---ULT-----TENS--------> --1------2---------3-------4-------5-----------6---------7-------8-------9---- 1 0 ( 0 0 0) 897 ( 229 897 0) 2 0 ( 0 0 0) 1715 ( 717 1715 0) 3 0 ( 0 0 0) 1412 ( 732 1412 0) 11.3.1 S T E E L A T S U P P O R T S T O P B O T T O M As DIFFERENT REBAR CRITERIA As DIFFERENT REBAR CRITERIA JOINT (mm^2) <---ULT-----MIN---------> (mm^2) <---ULT-----MIN---------> --1------2---------3-------4-------5-----------6---------7-------8-------9---- 1 1121 ( 0 1121 0) 0 ( 0 0 0) 2 4221 ( 4221 1599 0) 0 ( 0 0 0) 3 4533 ( 4533 1599 0) 0 ( 0 0 0) 4 1316 ( 0 1316 0) 0 ( 0 0 0)

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ADAPT - ST RUCTU RAL CO NCRETE SO FT W AR E SYS TEMA DA PT-PT V ersi on 6 .0 8 Date: 9/2 9/00 Time : 8 :14:0 7 AM File : Mn l5 _2m _L

1- PROJECT TITL E ADAPT PT Manu al1 .1 D ES IGN S TRIP Two -way eq uiva len t fr ame sl ab e xamp le fo r AD AP T (SI)

2 - MEM BER E LEV ATIO N [m] 5.75 0 8 .2 00 6.75 0 0 .90 0

3 - TOP R EBAR



3 .3 A DA PT se lected

3 .4 A DA PT se lected 2 1 7-4m m X43 80 mm1 9 -4 mm X2 04 0 m m

3 16 -4 mm X2 00 0 m m

4 1 8-4m m X46 80 mm

5 18 -4 mm X2 10 0 mm

7 11 -4m m X 318 0 mm

4 - TENDON PROFILE

4 .2 D atum L ine

4 .3 C GS Distan ce [mm]4 .5 F orce

13 0 2 5 23 5[1 23 8 kN ]

2 35 2 5 2 35[ 12 38 kN ]

23 5 2 5 15 0[1 65 0 kN ]

1 50 1 35 13 0[1 65 0 kN ]

5 - BOTTOM R EBAR5 .1 U ser se lected


5 .3 A DA PT se lected

5 .4 A DA PT se lected 6 4 -8 mm X3 48 0 m m 8 2-8 mm X33 00 m m

9 1-8 mm X26 20 m m

6 - REQUIRED & PROVIDED BARS

6 .1 T op B ar s

[ mm2]

req uired p ro vide d

6 .2 B ottom B ar s

ma x

ma x

0 0E +0 01 2E +0 2

2 4E +0 23 6E +0 24 8E +0 2

1 1E +0 22 2E +0 2

3 77 7

89 7

4 53 3

1 71 5

4 35 8

1 41 2

1 31 6

0

7 - PUNC HING SH EAR OK =Acce ptab le

NG =N o G ood *=n ot ap plicable

or n ot pe rformed

- --

*

.6 5

OK

.6 5

OK

-- -

*

7 .1 S tre ss Ra tio

7 .2 S tatus

8 - LEGEND Stre ssing En d Dea d En d

9 - DESIGN PARAMETERS9 .1 Co de : AC I f 'c = 2 8 N/m m

2 fy = 46 0 N /m m

2 (l on gi tud in al ) fy = 4 6 0 N/m m

2 (sh ea r) fpu = 1 8 60 N/mm

2

9 .2 R eb ar Cove r: T op = 2 5 mm Bo tto m = 2 5 mm Reb ar Ta ble: A S TM - US Cu stoma ry ba rs (N on -re distr ibu te d Mo men ts)

9 .3 S tre ssin g: fp j = .8 fpu

9 .4 S tra nd Ar ea = 99 mm2

10 - D ESIGNER'S NOTES

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15 - REINFORCEMENT DUE TO MOMENTS FROM LATERAL FORCES ============================================================================== o Lateral moments are considered with positive and reversed directions o Percentage of post-tensioning considered in resisting lateral moments= 100 % o Percentage of post-tensioning for moments transfer to columns = 20 % o Factored moments calculated are the larger from the followings equations i ) Mu = (1.05Md + 1.28Ml + 1.00Msec + 1.28Mlat) ii ) Mu = ( .90Md + .00Ml + 1.00Msec + 1.30Mlat) Where, Md = dead load moments; Ml = live load moments; Msec = secondary moments; and Mlat = lateral moments. 15.1 INPUTTED LATERAL MOMENTS AND THE RESULTING COMBINED MOMENTS kNm <- I N P U T -> <------- CALCULATED FACTORED SPAN MOMENTS Mu ------> LATERAL MOMENTS LEFT MID-SPAN RIGHT span left right neg------pos neg------pos neg------pos -1------2--------3----------4--------5---------6--------7---------8--------9-- 1 .00 -86.77 .00 26.40 .00 268.18 -598.57 .00 2 141.00 -141.00 -691.01 .00 .00 315.30 -771.70 .00 3 108.50 .00 -721.34 .00 .00 381.24 -20.37 .00 Note: Moments listed under 4,5,8,9 are reduced to face-of-support, if applicable. For distribution of moments see file LATBM.DAT 15.2 COLUMN MOMENTS AND MOMENTS TO BE TRANSFERRED OVER LIMITED SLAB/BEAM WIDTH <-- GAMMA*(UNBALANCED JOINT MOMENT) --> LEFT RIGHT MAX COLUMN MU PT JNT GAMMA neg------pos neg------pos neg------pos kN -1-----2----------3--------4---------5--------6---------7--------8---------9-- 1 1.00 .00 .00 .00 26.40 .00 26.40 247.60 2 .56 -145.86 .00 -171.60 .00 -305.88 259.99 247.60 3 .56 -183.48 .00 -163.87 .00 -292.11 327.07 330.00 4 1.00 .00 .00 .00 .00 -22.21 .00 330.00 Note: Moments listed under 3,4,5,6 are reduced to face-of-support, if applicable. Values in columns 7 and 8 are the sum of lower and upper column moments. GAMMA = Fraction of moment taken by flexure of a limited slab width (ACI-318) PT = PT force assumed available to resist the unbalanced moment 15.3 LEGENDS AND NOTES FOR MILD STEEL Columns 2 and the like in following block list total rebar due to lateral forces. These are not in addition to other considerations reported in preceding blocks. For details of rebar reinforcement refer to file LATSTL.DAT 15.4 SELECTION OF REBAR A T M I D - S P A N <------ T O P S T E E L ----> <----- B O T T O M S T E E L ---> SPAN (mm^2) Ult SELECTION (mm^2) Ult SELECTION -1----2-----3----4-----------5------------6-----7-----8-----------9-------- 1 2 3 20( 20 ) 1 #13 x 1275 mm

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15.5 SELECTION OF REBAR AT S U P P O R T S <------ T O P S T E E L ----> <----- B O T T O M S T E E L ---> JNT (mm^2) Ult Trans SELECTION (mm^2) Ult Trans SELECTION -1-----2----3-----4----------5-------------6----7------8-----------9---------- 1 2 3998( 3998 1206) 57 #10 x 3965 mm 0 3 3980( 3980 1160) 57 #10 x 3928 mm 0 4 15.6 DISTANCE OF INFLECTION POINTS (limit of zero rebar) FROM SUPPORTS ( m ) <-- T O P B A R S --> <-- BOTTOM B A R S --> JOINT TO LEFT TO RIGHT TO LEFT TO RIGHT ---1-------------2----------------3-------------------4----------------5------ 1 .00(1) .00(1) .00(1) .00(1) 2 1.73(1) 1.64(1) .00(1) .00(1) 3 1.64(1) 1.69(1) .00(1) 4.39(1) 4 .00(1) .90(1) 1.69(1) .90(1) Legend: 1 = Common Case of rebar 2 = Rebar is needed continuosly over the entire span 3 = Range of rebar requirement is not fully explicit in this table. Refer to either the print plot or detailed printout of rebar at 1/20th points (file "LATSTL.DAT")

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ADAPT STRUCTURAL CONCRETE SOFTWARE SYSTEM DATE: Sep 27,2000 TIME: 15:25 Data ID: Mnl5_2m_ Output File ID: LATSTL.DAT ============================================================================== SUMMARY OF REBAR REQUIRED AT 1/20TH POINTS DUE TO ULTIMATE LATERAL MOMENTS Note: This is NOT in addition to rebar from other considerations Note: for LEFT CANTILEVER (if any) X/L= 0.00 is at tip of cantilever, and X/L= 1.00 is at first support SPAN = 1 LENGTH = 5.75 meter; CLEAR from .10 to 5.53 m X/L X <--Reinforcement (mm^2)--> m TOP BOTTOM ------------------------------------------------------------------------------ .00 .00 .05 .29 .00 .00 .10 .57 .00 .00 .15 .86 .00 .00 .20 1.15 .00 .00 .25 1.44 .00 .00 .30 1.73 .00 .00 .35 2.01 .00 .00 .40 2.30 .00 .00 .45 2.59 .00 .00 .50 2.88 .00 .00 .55 3.16 .00 .00 .60 3.45 .00 .00 .65 3.74 .00 .00 .70 4.03 .00 .00 .75 4.31 244.98 .00 .80 4.60 718.45 .00 .85 4.89 1169.76 .00 .90 5.18 1577.02 .00 .95 5.46 2589.25 .00 1.00 5.75 SPAN = 2 LENGTH = 8.20 meter; CLEAR from .22 to 7.97 m X/L X <--Reinforcement (mm^2)--> m TOP BOTTOM ------------------------------------------------------------------------------ .00 .00 .05 .41 2963.37 .00 .10 .82 1446.07 .00 .15 1.23 436.80 .00 .20 1.64 .00 .00 .25 2.05 .00 .00 .30 2.46 .00 .00 .35 2.87 .00 .00 .40 3.28 .00 .00 .45 3.69 .00 .00 .50 4.10 .00 .00 .55 4.51 .00 .00 .60 4.92 .00 .00 .65 5.33 .00 .00 .70 5.74 .00 .00 .75 6.15 .00 .00 .80 6.56 .00 .00 .85 6.97 452.61 .00 .90 7.38 1386.37 .00 .95 7.79 2884.13 .00 1.00 8.20

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SPAN = 3 LENGTH = 17.00 feet ; CLEAR from .75 to 16.42 ft X/L X <--Reinforcement (in^2)--> ft TOP BOTTOM ------------------------------------------------------------------------------ .00 .00 .05 .85 4.39 2.06 .10 1.70 3.78 1.76 .15 2.55 3.19 1.47 .20 3.40 2.62 1.18 .25 4.25 2.07 .89 .30 5.10 1.54 .59 .35 5.95 1.03 .29 .40 6.80 .53 .00 .45 7.65 .05 .00 .50 8.50 .00 .00 .55 9.35 .00 .00 .60 10.20 .09 .23 .65 11.05 .37 .64 .70 11.90 .67 1.04 .75 12.75 .98 1.43 .80 13.60 1.33 1.82 .85 14.45 1.70 2.20 .90 15.30 2.09 2.58 .95 16.15 2.49 2.94 1.00 17.00 REBAR REQUIRED AT FACES OF SUPPORTS ============================================================================== SPAN = 1 LENGTH = 64.00 feet ; CLEAR from .58 to 63.25 ft X/L X <--Reinforcement (in^2)--> ft TOP BOTTOM ------------------------------------------------------------------------------ face of support at left .01 .58 1.10 1.63 face of support at right .99 63.25 6.56 .00 SPAN = 2 LENGTH = 55.00 feet ; CLEAR from .75 to 54.25 ft X/L X <--Reinforcement (in^2)--> ft TOP BOTTOM ------------------------------------------------------------------------------ face of support at left .01 .75 6.42 .00 face of support at right .99 54.25 3.64 1.32 SPAN = 3 LENGTH = 17.00 feet ; CLEAR from .75 to 16.42 ft X/L X <--Reinforcement (in^2)--> ft TOP BOTTOM ------------------------------------------------------------------------------ face of support at left .04 .75 4.46 2.09 face of support at right .97 16.42 2.62 3.05

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REBAR REQUIRED AT FACES OF SUPPORTS ============================================================================== SPAN = 1 LENGTH = 5.75 meter; CLEAR from .10 to 5.53 m X/L X <--Reinforcement (mm^2)--> m TOP BOTTOM ------------------------------------------------------------------------------ face of support at left .02 .10 .00 .00 face of support at right .96 5.53 2911.10 .00 SPAN = 2 LENGTH = 8.20 meter; CLEAR from .22 to 7.97 m X/L X <--Reinforcement (mm^2)--> m TOP BOTTOM ------------------------------------------------------------------------------ face of support at left .03 .22 3998.20 .00 face of support at right .97 7.97 3980.49 .00 SPAN = 3 LENGTH = 6.75 meter; CLEAR from .22 to 6.65 m X/L X <--Reinforcement (mm^2)--> m TOP BOTTOM ------------------------------------------------------------------------------ face of support at left .03 .22 3376.07 .00 face of support at right .99 6.65 .00 .00 RIGHT CANTILEVER LENGTH = .90 meter; CLEAR from .10 to .90 m X/L X <--Reinforcement (mm^2)--> m TOP BOTTOM ------------------------------------------------------------------------------ face of support .11 .10 .00 .00

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ADAPT STRUCTURAL CONCRETE SOFTWARE SYSTEM DATE: Sep 27,2000 TIME: 15:25 Data ID: Mnl5_2m_ Output File ID: LATBM.DAT ============================================================================== DISTRIBUTION OF LATERAL MOMENTS AT 1/20TH POINTS ALONG EACH SPAN TOGETHER WITH MAXIMA OF POSITIVE AND NEGATIVE FACTORED MOMENTS AT EACH POINT USING THE FOLLOWING TWO LOAD COMBINATION EXPRESSIONS : i ) Mu = (1.05Md + 1.28Ml + 1.00Msec + 1.28Mlat) ii ) Mu = ( .90Md + .00Ml + 1.00Msec + 1.30Mlat) Where, Md = dead load moments; Ml = live load moments; Msec = secondary moments; and Mlat = lateral moments. Units : m and (kNm) SPAN = 1 LENGTH = 5.75 meter (Net span from .10 to 5.53 m ) Applied lateral moments Maxima of combined moments X/L X positive reversed largest smallest ---1-------2-------------3------------4---------------5-------------6----- .00 .00 .00 .00 .00 .00 .05 .29 -4.34 4.34 72.58 31.43 .10 .57 -8.68 8.68 134.99 57.33 .15 .86 -13.02 13.02 187.22 77.70 .20 1.15 -17.35 17.35 229.29 92.55 .25 1.44 -21.69 21.69 261.20 101.89 .30 1.73 -26.03 26.03 282.92 105.69 .35 2.01 -30.37 30.37 294.49 103.97 .40 2.30 -34.71 34.71 295.89 96.74 .45 2.59 -39.05 39.05 287.12 83.97 .50 2.88 -43.38 43.38 268.18 65.68 .55 3.16 -47.72 47.72 239.07 41.87 .60 3.45 -52.06 52.06 199.79 12.54 .65 3.74 -56.40 56.40 150.35 -22.32 .70 4.03 -60.74 60.74 95.22 -64.75 .75 4.31 -65.08 65.08 60.59 -145.64 .80 4.60 -69.42 69.42 20.45 -236.70 .85 4.89 -73.75 73.75 -25.22 -337.92 .90 5.17 -78.09 78.09 -76.42 -449.31 .95 5.46 -82.43 82.43 -133.14 -570.87 1.00 5.75 -86.77 86.77 -195.38 -702.59 SPAN = 2 LENGTH = 8.20 meter (Net span from .22 to 7.97 m ) Applied lateral moments Maxima of combined moments X/L X positive reversed largest smallest ---1-------2-------------3------------4---------------5-------------6----- .00 .00 141.00 -141.00 -151.41 -803.17 .05 .41 126.90 -126.90 -65.57 -603.05 .10 .82 112.80 -112.80 9.04 -422.56 .15 1.23 98.70 -98.70 72.43 -261.67 .20 1.64 84.60 -84.60 124.57 -120.41 .25 2.05 70.50 -70.50 181.73 -17.82 .30 2.46 56.40 -56.40 247.67 48.52 .35 2.87 42.30 -42.30 294.00 103.63 .40 3.28 28.20 -28.20 320.72 147.51 .45 3.69 14.10 -14.10 327.82 180.15 .50 4.10 .00 .00 315.30 201.55

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.55 4.51 -14.10 14.10 319.27 175.06 .60 4.92 -28.20 28.20 303.62 137.34 .65 5.33 -42.30 42.30 268.36 88.39 .70 5.74 -56.40 56.40 213.49 28.21 .75 6.15 -70.50 70.50 140.09 -43.21 .80 6.56 -84.60 84.60 94.09 -171.68 .85 6.97 -98.70 98.70 36.87 -321.49 .90 7.38 -112.80 112.80 -31.59 -490.92 .95 7.79 -126.90 126.90 -111.28 -679.97 1.00 8.20 -141.00 141.00 -202.21 -888.62 SPAN = 3 LENGTH = 6.75 meter (Net span from .22 to 6.65 m ) Applied lateral moments Maxima of combined moments X/L X positive reversed largest smallest ---1-------2-------------3------------4---------------5-------------6----- .00 .00 108.50 -108.50 -226.05 -835.79 .05 .34 103.07 -103.07 -143.79 -666.37 .10 .68 97.65 -97.65 -69.14 -510.63 .15 1.01 92.22 -92.22 -2.10 -368.58 .20 1.35 86.80 -86.80 57.32 -240.23 .25 1.69 81.38 -81.38 109.14 -125.57 .30 2.03 75.95 -75.95 169.83 -44.13 .35 2.36 70.53 -70.53 243.22 6.57 .40 2.70 65.10 -65.10 302.92 49.65 .45 3.04 59.67 -59.67 348.93 85.13 .50 3.38 54.25 -54.25 381.24 112.99 .55 3.71 48.83 -48.83 399.86 133.23 .60 4.05 43.40 -43.40 404.79 145.86 .65 4.39 37.97 -37.97 396.03 150.89 .70 4.72 32.55 -32.55 373.57 148.31 .75 5.06 27.13 -27.13 337.43 138.11 .80 5.40 21.70 -21.70 287.59 120.30 .85 5.74 16.27 -16.27 224.07 94.88 .90 6.07 10.85 -10.85 146.84 61.84 .95 6.41 5.43 -5.43 55.93 21.20 1.00 6.75 .00 .00 -27.06 -48.67 SPAN = 1 LENGTH = 5.75 meter (Net span from .10 to 5.53 m ) X/L X positive reversed largest smallest ---1-------2-------------3------------4---------------5-------------6----- .02 .10 -1.51 1.51 26.40 11.56 .96 5.53 -83.37 83.37 -146.16 -598.57 SPAN = 2 LENGTH = 8.20 meter (Net span from .22 to 7.97 m ) X/L X positive reversed largest smallest ---1-------2-------------3------------4---------------5-------------6----- .03 .22 133.26 -133.26 -102.94 -691.01 .97 7.97 -133.26 133.26 -150.96 -771.70 SPAN = 3 LENGTH = 6.75 meter (Net span from .22 to 6.65 m ) X/L X positive reversed largest smallest ---1-------2-------------3------------4---------------5-------------6----- .03 .22 104.88 -104.88 -170.38 -721.34 .99 6.65 1.61 -1.61 -7.79 -20.37

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Data Block 15.1, Calculated Factored Span Moments Mu

The results of data block 15.1 will be verified for the first interior joint.

The moments Md, Ml and Msec can be found on the Results Report. The values are

given below with the data block and column (i.e. B7.1,C4) shown to the right.

Left Face of Support (right of span #1):

Md = -337.0 (B7.1, C4)M1 = -145.90 (B7.2, C6)Msec = 48.75 (B10.2, C4)Mlat = -83.37 (LATBM.DAT)

Right Face of Support (left of span #2):

Md = -352.60 (B7.1,C1)M1 = -149.50 (B7.2, C2)Msec = 41.16 (B10.2, C2)Mlat = 133.27 (LATBM.DAT)

Up to eight moment combinations are evaluated at each 1/20th point along a span.Since live loading was not skipped in MNL5-2, only four combinations are used tocalculate Mu at each section:

1.05Md + 1.28Ml + 1.00Msec + 1.28Mlat (i)1.05Md + 1.28Ml + 1.00Msec - 1.28Mlat (ii)0.90Md + 0.00Ml

+ 1.00Msec + 1.30Mlat (iii)

0.90Md + 0.00Ml + 1.00Msec - 1.30Mlat (iv)

Values are calculated at the face of the first interior support:

Equation Mu

Left FOS Right FOS (i) -598.56 -349.84 (ii) -385.14 -691.02 (iii) -362.93 -103.33 (iii) -146.17 -449.43

Note: FOS = Face-of-Support

The maximum and minimum values for each section are listed in columns 5 and 6 offile LATBM.DAT. The governing value of Mu for joint 2 is selected from these valuesand is reported in column 8 of data block 15.1 as -598.56 kNm for the left face-of-support (FOS) and in column 4 as -691.02 for the right FOS.

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Data Block 15.2

Since this is a two-way slab, a fraction of the unbalanced moment must be transferredover the a strip.

At joint 2, γ is calculated using the equation from ACI Section 13.5.3.2:

γ = {1/(1 + (2/3)*[(c1+d)/(c2+d)]1/2}

(c1 + d) = 1600 mm (B2.3,C4,C5)(c2

+ d) = 1100 mm (B2.3,C3)

γ = {1/(1 + (2/3)*[1600/1100]1/2}= 0.5543 (ADAPT 0.56, B15.2, C2)

Columns 3 through 6 give the unbalanced joint moments used for calculation of therebar required for transfer of the unbalanced moment. The following table valuesshows values for the four combinations. Note that the Mu values are taken at the faceof support.

The maximum values are:

Left, negative = -145.86 kNm (ADAPT -145.95, B15.2, C3)Left, positive = 0.00 kNm (ADAPT 0.00, B15.2, C4)Right, negative= -171.60 kNm (ADAPT -171.60, B15.2, C5)Right, positive= 0.00 kNm (ADAPT 0.00, B15.2, C6)

The moment transferred to the column is:

(Mu right of joint) - (Mu left of joint)

Mu Equation Span 1

X/L = 0.961 Span 2

X/L = 0.034

��u

(i) -598.56 -349.84 0.56*(-248.72) = -139.28, left (ii) -385.14 -691.02 0.56*(-305.88) = -171.29, right (iii) -362.93 -103.33 0.56*(-260.00) = -145.60, left (iii) -146.17 -449.43 0.56*(-303.26) = -169.83, right

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Negative Column Mu = -305.88 kNm (ADAPT -305.92, B15.2, C7)

Positive Column Mu = 259.99 kNm (ADAPT 260.16, B15.2, C8)

Data block 15.2, column 9 indicates the amount of post-tensioning available to beused for transfer of unbalanced moment, and is verified by multiplying the user-selected parameter times total PT force provided, data block 9.3, column 2.

0.20 x 1238 = 247.60kN (ADAPT 247.60, B15.2, C9)

Note that this percentage is independent of the percentage entered as being effectivein resisting lateral moments. The amount of post-tensioning considered effective fortransfer of the unbalanced moment will be the full amount of the post-tensioningmultiplied by the amount entered as PT contributory to transfer of unbalanced mo-ment in the slab.

Data Blocks 15.3 Through 15.5

Data blocks 15.3 through 15.5 report the amount of mild reinforcement required toresist the lateral forces. The calculated areas of steel are based on the maximumultimate moments, Mu, resulting from the lateral load combinations specified by theuser (data block 15.1) and the fraction of the unbalanced joint moment to be trans-ferred (data block 15.2).

For the moment Mu calculated in data block 15.1, verification of the mild reinforce-ment is carried out in the same way as the rebar reported in data block 11. The gen-eral method is to perform an analysis to verify that the section capacity, given theamount of mild reinforcement reported, is equal to the ultimate span or unbalancedjoint moments.

The user is referred to Chapter 7 of the Manual, Verification, Section 7.4.1, Rein-forcement Required for Strength. For the case of the top steel required at joint two inexample MNL5-2M, the user begins with the total area of steel, 3998 mm2

, reported

both in LATSTL.DAT and data block 15.5, column 3 of the Results Report, which isthe total steel based on the larger of either the transfer or ultimate moments. The

Once again, ADAPT considers all four combinations and selects the governingmaximum values. The maximum values are:

Mu Equation Span 1

X/L = 0.961 Span 2

X/L = 0.034

(Mu right - Mu left)

(i) -598.56 -349.84 -248.72 (ii) -385.14 -691.02 -305.88 (iii) -362.93 -103.33 -260.00 (iii) -146.17 -449.43 -303.26

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procedure of Chapter 7, Section 7.4.1, can be used to check that the area has beencorrectly determined.

Keep in mind that the mild steel is the amount required for the Lateral Analysiscombinations. The amounts must be compared to those calculated for the gravity orother load cases to determine which load case governs the design. For the secondsupport of the current example, the user compares the lateral and gravity steelamounts as follows:

Mild rebar due to combined actions = 4221 mm2 (B11.3.1, C2)Mild rebar due to gravity only = 3998 mm2 (B15.5, C2)

Therefore, the lateral case governs at this location. The mild steel to be provided is4221 mm2

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3.3.7 DISCUSSION OF LATERAL LOADING TREATMENT

The structural models used for gravity and lateral loads are different. For gravity loading, theEquivalent Frame approach is typically used. In the Equivalent Frame approach, each line ofcolumns along with their respective slab tributaries is considered as a plane frame (Fig. 3.3.7-1(a)). Each level is treated as a single story frame with the associated columns fixed at theirfar ends (Fig. 3.3.7-1(b)). The basic difference between the Equivalent Frame approach anda regular plane frame is that the Equivalent Frame approach recognizes that a column in theactual three dimensional structure is subject to a smaller moment than what it is calculatedfrom the plane frame. The reduced column stiffness used in the Equivalent Frame modelinggreatly improves the accuracy of the frame approximation.

For a lateral analysis (Fig. 3.3.7-2), vertical frames encompassing the horizontal extent of thebuilding are handled as multistory plane frames. Due to concrete cracking and plate geom-etry however, the entire tributary width of the slab does not participate in the frame behavior.With prestressed slabs, 50% of the slab tributary is usually considered effective in resistingwind/earthquake loads. With non-prestressed slabs, 33% of the tributary is assumed effectivefor lateral loading.

Figure 3.3.7-3 is an illustration of the frame stiffnesses for the gravity and lateral analyses asthey relate to the slab tributaries. For the gravity loading condition, the equivalent frameapproximation is expressed in terms of effective slab weight, in order to afford comparisonbetween the gravity and lateral frame behaviors. It is noted that for gravity loading a largereffective width is used. This nonconformity in modeling necessitates two independentanalyses, one for the gravity and the other for the later loading, each having a different set offrame stiffness. The solutions obtained from the two analyses must be combined, as illus-trated in Fig. 3.3.2-1, in order to design for critical combinations. Observe that since noserviceability stress checks are required for the lateral loading, only the secondary momentsdue to post-tensioning are included in the combinations of Fig. 3.3.2-1.

Beams and slabs are typically sized and designed on the basis of the gravity loading analysis.They are subsequently checked for combinations with lateral loading. Nonprestressed rein-forcement is added if the initial gravity design is not adequate,. The combination of gravityand lateral moments may result in moment reversals at the joints (Fig. 3.3.2-1(f)), in whichcase the post-tensioning falls in the compression zone (Fig. 3.3.7-4). In such conditions, theamount of rebar in the tension zone must be adequate to (i) compensate for the tensile forcein the prestressing tendon, and (ii) develop the moment imposed on the section.

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FIGURE 3.3.7-1

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FIGURE 3.3.7-2

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FIGURE 3.3.7-3

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FIGURE 3.3.7-4

3.3.8 SPECIFIC FEATURES FOR CODES OTHER THAN ACI

Ultimate moments and unbalanced joint moments are calculated in the same manner for alldesign codes. The required reinforcement is determined according to the specific designcode, however. If the British code were used for the ADAPT-PT run, BS8110 requirementswould have been automatically used by the “lateral” module.. Likewise, if the Canadian codewere used for the ADAPT-PT run, CAN3-A23.3-94 requirements would of been invoked.

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3.4 FRICTION AND LONG TERM LOSSES POST-PROCESSOR

The Friction and Long Term Losses post-processor calculates prestress losses for designs thathave been executed using the Force Selection mode. In order to enter the information re-quired for the calculations, the Force/Tendon Section | Friction Calculations button on theCriteria – Calculation Options screen must be chosen during data entry.

The output of the program consists of:

• a reflection of the input data;• a listing of the long-term stress loss constituents and the total long-term stress loss;• the distribution of stress immediately after tensioning and seating of the tendons;• the location and magnitude of the maximum stresses; and,• the design elongations.

3.4.1 BACKGROUND

The stresses in a prestressing strand normally vary along its length and decrease withtime. The principal factors affecting the distribution of stress along a strand are:

• friction losses during stressing;• retraction of strand as it seats and locks into the anchorage device (seating

loss);• elastic shortening of the concrete;• shrinkage of the concrete;• creep of the concrete; and,• relaxation of the steel.

Other factors such as changes in temperature and flexing of the structure under load-ing also affect the stresses in a strand, but these do not necessarily result in a perma-nent lowering of stress level and are not typically considered as stress losses.

The total prestress loss for unbonded, low-relaxation tendons is typically 20 percentof the jacking stress. A lump sum stress loss of 30 ksi (14%) was assumed for severalyears for prestressed members, since there is no friction loss in prestressing. Thedevelopment of low-relaxation strands and results of subsequent studies prompted acall for more exact estimates. A rigorous evaluation of stress losses is both timeconsuming and complex, however. Precise calculations for each tendon are notusually warranted in most residential and commercial buildings; studies have indi-cated that reliable solutions can be obtained with a number of simplifying assump-tions.

The commentary for ACI 318, Section 18.6.1 states the following:

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“Lump sum values of prestress losses for both pre-tensioned andpost-tensioned members which were indicated in pre-1983 editions of thecommentary are considered obsolete. Reasonably accurate estimates ofprestress losses can be easily calculated in accordance with recommendationsin Reference 18.6 which include considerations of initial stress level (0.70fpuor higher), type of steel.”

Reference 18.6 presents the results of a study initiated by ACI/ASCE committee 423,directed by Paul Zia and reported in Concrete International (June 1979). The Frictionand Long-term Losses uses the equations given in this article to calculate long-termlosses. The stress losses due to friction and seating of tendon are based on ACI 318.Research on friction losses and the background to the proposed procedures for theircalculation is reported in numerous publications including several listed in the Refer-ences at the end of this section.

It is assumed that the various factors such as friction, creep, and shrinkage that affectthe stress losses are independent from one another. Hence, the loss due to each factormay be computed separately. The total stress loss in a tendon is the sum of the indi-vidually calculated losses.

In addition to the stress loss factors discussed above, the effective prestressing in amember may be affected by its connections to other structural members that restrainits movement. These factors are not taken into account in the Friction and Long TermLosses post-processor. They should be accounted for based on rational proceduresthat consider equilibrium of forces and strain compatibility. Aalami and Barth (1987)discuss the consequences of restraint in commercial buildings.

3.4.2 STRESS DISTRIBUTION

The stress losses along a tendon are illustrated in Fig. 3.4.2-1. Figure 3.4.2-1(a)shows a beam with a continuous tendon stressed at both ends. It is assumed that theleft end is stressed first. Figure 3.4.2-1(b) shows the distribution of stress along thestrand during stressing, prior to locking off the strand. The jacking stress is com-monly specified at 0.80fpu, where fpu is the ultimate strength of strand. The smoothcurve is a simplification of the actual distribution for illustration purposes however.The actual shape of the curve is determined by the tendon profile and friction param-eters.

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FIGURE 3.4.2-1 (cont’d. . . .)

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(cont’d. . . .) FIGURE 3.4.2-1

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Figure 3.4.2-1(c) is the distribution after the strand is locked off at the left end of thebeam. Observe that the initial stress is partially lost over a length of strand at the leftend marked XL. This is the result of the retraction of the strand at the stressing endwhile the wedges are being seated. Per ACI 318, Chapter 18. the maximum permis-sible stress value immediately after lock-off and away from anchorage device is0.74fpu. The maximum stress occurs at XL. The maximum permissible stress at theanchorage immediately after seating of the strand is 0.7fpu.

The seating loss, also referred to as anchorage set or draw-in, is typically 3/8 to ¼ ofan inch (6 to 8 mm). For short strands, and/or larger values of seating loss, the lengthXL may extend to the far end of the strand. Stressing rams with power seating capa-bility will minimize the seating loss. Note that the retraction of the strand is resistedby the same friction forces that resisted the initial stressing. The stress diagram alonglength XL thus has the same gradient as the remainder of the curve, but in the oppo-site direction.

In most cases, jacking of the tendon at right end, Fig. 3.4.2-1(d), raises the stresses toabout the mid-point of the tendon and the stress diagram will have a second peak atXR. The distribution of stress immediately after the strand is seated at the right isshown in Fig. 3.4.2-1(e). Note that the lock-off stresses at the left and right are notgenerally the same unless the tendon is symmetrical about its mid-point.

The average initial stress is the average of this stress distribution. This value is usedby some designers to calculate the stresses in unbonded post-tensioned structures atthe transfer of post-tensioning. Transfer of post-tensioning refers to the loadingcondition immediately after stressing, prior to the application of live loading and theinfluences of long-term stress losses. It is also referred to as the “lock-off stress”.

As long-term stress losses occur, the stress in strand is reduced along its length.Figure 3.4.2-1(f) shows a schematic of the stress distribution after all losses havetaken place. The following should be noted with respect to the final distribution ofstress:

• Long-term stress losses along a tendon are not constant. Even under uniformgeometry and exposure conditions, differences in concrete stress along astrand result in non-uniform losses. In the design of commercial buildings,however, it is common practice to calculate a representative long-term lossvalue for the entire member when unbonded tendons are used. The averageprecompression in concrete is used to calculate the representative stress loss.The average precompression is calculated using the effective prestressingforce and gross cross-section of concrete. In bonded tendon construction,long-term losses are strictly a function of concrete strain at location of tendonalong the length of member

• Long-Term stress losses are obviously a function of time. The relationshipsdeveloped by the ACI/ASCE committee refer to a time at which over 90

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percent of the losses have taken place. For common commercial buildingsthis period is between 2 and 2 1/2 years. The stress loss rates for shrinkage,creep and relaxation are not the same however. The curve shown in Fig.3.4.2-2 may be used as a first approximation to estimate the combined stresslosses for concrete at earlier ages. This diagram is compiled from the com-bined effects of shrinkage and creep using data from the PCI Design Hand-book.

FIGURE 3.4.2-2

The stress diagram computed from the friction formulas given in ACI 318 and shownin the Fig. 3.4.2-2 represent the maximum possible stress gradient attainable from thefriction coefficients. The diagram is constructed with the maximum gradient at allpoints. With unbonded strands, flexing of the member due to applied loading, tem-perature changes, shrinkage and creep can only reduce the stress gradient. Thus therecould actually be a flattening of the diagram toward a more uniform stress distributionalong the length of the tendon. This is the premise for the use of “effective” stress indesign of post-tensioned members reinforced with unbonded tendons. There do notappear to be any conclusive studies that would quantify the extent of the stress redis-tribution however.

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A paper from University of Texas at Austin (Burns et al. 1991) indicates that thestress distribution in unbonded tendons does not significantly equalize with time.Further tests are needed to clarify the concept of equalization of force with time alongunbonded tendons.

If a final effective force design approach is used, the outcome of the design is aneffective force to be provided by post-tensioning. The effective force is the value thatis shown on the structural drawings and in the calculations. The question of whetherthe effective force is based on average stresses, local stresses, or other considerationsis not applicable during design.

At the shop drawing preparation phase, the effective forces must be replaced by thenumber of strands. In theory, the actual stresses in the strand at each location shouldbe used to arrive at the number of strands required at that location. Because of thelack of information, and the complexity of this approach, however, an effective stressis typically used when designing commercial buildings with unbonded tendons. Theeffective stress is the average initial stress (Fig. 3.4.2-1(e)), minus a representativelong-term stress loss value calculated for the entire member. Some engineers refer tothe effective stress as the design stress.

When the design is done using a system bound approach, the structural calculationsare preceded by a friction and long-term loss computation using parameters particularto the post-tensioning supplier. The structural calculations can thus determine thenumber and location of the strands. In this case, the calculation of the design stress isof prime importance to the structural designer. The ACI code specifies that thestresses used in structural computations should be derived with due considerations toimmediate and long-term losses. Unless satisfactory research shows otherwise, theuse of an effective stress does not seem justified in a system bound design approach.

3.4.3 FRICTION AND SEATING LOSS CALCULATIONS

Figure 3.4.2-1(a) shows a typical post-tensioning tendon profile. When the jackingforce, P

j, is applied at the stressing end, the tendon will elongate in accordance with

the strength of materials formula:

∆ = ∫ Pdx/AE

Where,

dx = the element of length along tendon;A = cross-sectional area of the tendon; and, E = modulus of elasticity of the prestressing steel (typically taken as either

28000 or 28500 ksi).

This elongation will be resisted by friction between the strand and its sheathing orduct, however. As a result of this friction, there will be a drop in the force in the

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tendon with distance from the jacking end. The friction is comprised of two effects:curvature friction which is a function of the tendon’s profile, and wobble frictionwhich is the result of minor horizontal or vertical deviations from the intended pro-file. Curvature friction is greatest when there are short spans with fairly large changesin profile.

The stress at any point along a strand is related to the jacking stress through thefollowing relationship:

Px = Pj*e-(µα + KX)

Where,

Px = stress at distance x from the jacking point;P

j= stress at jacking point;

m = coefficient of angular friction;a = total angle change of the strand in radians from the stressing point to

distance X;X = distance from the stressing point; and,K = wobble coefficient of friction expressed in radians per unit length of

strand.

TABLE 3.4.3-1 FRICTION COEFFICIENTS FOR POST-TENSIONING TENDONS

a - RANGE OF VALUES

Type of Tendon

Wobble coefficient K (radians per ft)

Curvature coefficient µ

Flexible tubing; non-galvanized 0.0005-0.0010 0.18-0.26 Galvanized 0.0003-0.0007 0.14-0.22 Rigid thin wall tubing; non-galvanized 0.0001-0.0005 0.20-0.30 Galvanized 0.0000-0.0004 0.16-0.24 Greased and wrapped 0.0005-0.0015 0.05-0.15 b - RECOMMENDED VALUES

Type of Tendon Wobble coefficient K (radians per ft)

Curvature coefficient µ

Flexible tubing; non-galvanized 0.00075 0.22 Galvanized 0.0005 0.18 Rigid thin wall tubing; non-galvanized 0.0003 0.25 Galvanized 0.0002 0.20 Greased and wrapped 0.0010 0.07

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Table 3.4.3-1, reproduced from the PTI Manual, gives friction coefficients for com-mon strand and duct materials. Note that unbonded, monostrand tendons are referredto as ‘Greased and Wrapped’ in this table. A similar table is given in ACI 318. Thepost-tensioning supplier should be consulted for friction coefficients of duct andcoating materials not shown.

Seating Losses

After they are stressed, tendons are typically anchored with two-piece conical wedges.The strand retracts when it is released and pulls the wedges into the anchorage device;this forces the wedges together and locks the strand in place. The stress loss due toseating is somewhat hard to calculate because the loss in elongation is fairly small (itdepends on both the jack and jacking procedure.) In addition, the loss in elongation(referred to as anchor set, or draw-in) is resisted by friction much as the elongationitself is resisted by friction.

Calculation of the stress loss is typically done as an iterative process; an anchor setinfluence length, lset, is chosen and the loss in force over this length is calculatedbased on the friction profile. An elongation loss is then calculated using the formula:

∆=∫ (Px dx/AE)

The anchor set length is adjusted until the calculated delta is reasonably close to theseating loss.

The stress loss is typically shown on force profile diagrams as the difference betweenthe jacking force and the lock-off force at the stressing end(s) of the member.

The stress loss due to seating the wedges is calculated from the following relation-ship:

a = (1/Es)* ∫ (final stress - initial stress)*dx

Where,

a = anchor set;Es = modulus of elasticity of tendon.

The integral is carried out over the range XL or XR (see Fig. 3.4.2-1). It may beinterpreted as the area between the pre- seating and post-seating stress levels dividedby the modulus of elasticity of strand. The distances XL and XR are calculated sothat the value of the integral equals the anchor set (see Fig. 3.4.3-1)

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FIGURE 3.4.3-1

The program calculates the stresses at 21 points in each span. Only three points arelisted in the short output however. The locations of these points for each tendonprofile type are shown in Figs. 3.4.3-2 and 3.4.3-3.

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FIGURE 3.4.3-2

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FIGURE 3.4.3-3

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The average stress is calculated as the area under the stress diagram divided by thelength of the tendon. Note that the slope of the “post-seating” stress line is the in-verse of the initial stress loss line. The elongation for the first stressing is the averagestress in the tendon after the first stressing, divided by the modulus of elasticity of thestrand. The elongation for the second stressing is the average stress in the tendondivided by the modulus of elasticity, minus the first elongation.

3.4.4 LONG-TERM STRESS LOSS PARAMETERS

The following describes the relationships given for long-term stress loss calculationsin (Zia et al., 1979).

Elastic Shortening of Concrete (ES)

Elastic shortening refers to the shortening of the concrete member as the post-tension-ing force is applied. If there is only one tendon in a member, there will be no loss dueto elastic shortening since the elastic shortening will have occurred before the tendonis locked into place. Generally, however there will be several tendons in a member.As each tendon is tensioned, there will be a loss of prestress in the previously ten-sioned tendons due to the elastic shortening of the member.

Since an unbonded tendon can slide within its sheathing, it typically does not experi-ence the same stress-induced strain changes as the concrete surrounding it. For thisreason, the average compressive stress in the concrete, fcpa, is typically used tocalculate prestress losses due to elastic shortening and creep for unbonded tendons.This relates these prestress losses to the average member strain rather than the strainat the point of maximum moment.

The equation given for calculating elastic shortening for unbonded tendons is:

ES = KesEs fcpa/Eci

Where,

Es is the elastic modulus of the steel;Eci is the elastic modulus of the concrete at time of prestress transfer;Kes = 0.5 for post-tensioned members when tendons are tensioned in sequen-

tial order to the same tension. With other post-tensioning procedures,Kes may vary from 0 to 0.5; and,

fcpa = average compressive stress in the concrete along the length of themember at the center of gravity (cgs) of the tendon immediately afterthe prestress transfer. Note that the stress at the cgs is larger than theaverage compression in a member.

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At the time they are stressed, the ducts in which bonded tendons are housed haveusually not been grouted. Thus, the elastic shortening equations for unbondedtendons would apply to these tendons as well.

Creep of Concrete (CR)

Over time, the compressive stress induced by post-tensioning causes a shortening ofthe concrete member. This phenomenon, the increase in strain due to a sustainedstress, is referred to as creep. Loss of prestress due to creep is proportional to the netpermanent compressive stress in the concrete. The initial compressive stress inducedin the concrete at transfer is subsequently reduced by the tensile stress resulting fromself-weight and superimposed dead load moments.

For members with unbonded tendons, the equation is:

CR = Kcr (Es / Ec) fcpa

For members with bonded tendons, the equation is:

CR = Kcr (Es / Ec) (fcir -fcds)

Where:

Ec = elastic modulus of the concrete at 28 days;

Kcr = 1.6 for post-tensioned members; and,fcds = stress in the concrete at the cgs of the tendons due to all sustained

loads that are applied to the member after it has been stressed

The difference in the equations is due to the fact that unbonded tendons do not experi-ence the same strains as the surrounding concrete. The prestress loss due to creep isthus more logically related to the average stress in the concrete. With bonded tendonshowever, once the duct is grouted the shortening of the concrete member due to creepwill result in a comparable shortening (loss of elongation) in the tendon.

For members made with sand-lightweight concrete, a 20% decrease in the value of Kcr

is suggested.

Shrinkage of Concrete (SH)

In the calculation of prestress losses, shrinkage is considered to be entirely a functionof water loss. Shrinkage strain is thus influenced by the member’s volume/surfaceratio and the ambient relative humidity. The effective shrinkage strain, esh is obtainedby multiplying the basic ultimate shrinkage strain, (esh)u, taken as 550 x 10-6, by thefactors (1-.06 V/S) and (1.5 - 0.015RH).

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esh = 550 x 10-6 (1-0.06 V/S)(1.5 - 0.015RH)= 8.2 x 10-6 (1-0.06V/S) (100 - RH)

The equation for losses due to shrinkage is:

SH = 8.2 x 10-6 Ksh Es (1-0.06 V/S) (100-RH)

Where:

V/S = volume to surface ratio;RH = relative humidity (percent), see Fig. 3.4.4-1.

Ksh = a factor which allows for the amount of shrinkage which willhave taken place before the prestressing is applied. For post-tensioned members, Ksh is taken from Table 3.4.4-1.

TABLE 3.4.4-1 SHRINKAGE CONSTANT Ksh DAYS* 1 3 5 7 10 20 30 60 Ksh 0.92 0.85 0.80 0.77 0.73 0.64 0.58 0.45

* DAYS refers to the time from the end of moist curing to the application ofprestressing. For stressing more than 60 days after curing, a value of 0.45 is assumed.

In structures that are not moist cured, Ksh is typically based on the time when theconcrete was cast. It should be noted that in most structures, the prestressing isapplied within five days of casting the concrete, whether or not it is moist-cured.

Note that the effective shrinkage strain is zero under conditions of 100% relativehumidity, i.e. if the concrete is continuously submerged in water.

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PCI Design HandbookANNUAL AVERAGE AMBIENT RELATIVE HUMIDITY, PERCENT

FIGURE 3.4.4-1

Relaxation of Tendon (RE)

Relaxation is defined as a gradual decrease of stress in a material under constantstrain. In the case of steel, it is the result of a permanent alteration of the grain struc-ture. The rate of relaxation at any point in time depends on the stress level in thetendon at that time. Because of other prestress losses, there is a continual reduction ofthe tendon stress which causes a corresponding reduction in the relaxation rate.

The equation given for prestress loss due to relaxation of the tendons is:

RE = [Kre - J*(SH + CR + ES)]*C

Where: Kre and J are a function of the type of steel and C is a function of both thetype of steel and the initial stress level in the tendon (fpi/fpu).

Table 3.4.4-2 gives values of Kre and J for different types of steel. The factor Jaccounts for the reduction in tendon stress due to other losses. As can be seen, therelaxation of low-relaxation tendons is approximately one-quarter that of stress-relieved tendons.

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Table 3.4.4-3 gives values for C. The values for stress-relieved and low-relaxationtendons are different because the yield stress for low relaxation tendons is higher thanthat of the same grade stress-relieved tendons. Although ACI allows a stress of 0.74fpu along the length of the tendon immediately after prestress transfer, the stress atpost-tensioning anchorages and couplers is limited to 0.70 fpu. In the absence of moreexact calculations, the ratio fpi/fpu is typically taken as 0.70 for unbonded post-tensioning. With very short tendons however, the loss due to anchor set may be suchthat fpi/fpu is considerably lower.

TABLE 3.4.4-2 STRESS RELAXATION CONSTANTS Kre AND J

Grade and type* Kre J

270 strand or wire 20000 0.15 250 strand or wire 18500 0.14 STRESS 240 wire 17600 0.13 RELIEVED 235 wire 17600 0.13 160 bar 6000 0.05 145 bar 6000 0.05 270 strand 5000 0.040 LOW 250 wire 4630 0.037 RELAXATION 240 wire 4400 0.035 235 wire 4400 0.035

* In accordance with ASTM A416-74, ASTM A421-76, ASTM A722-75. Linear interpolation is used for values between those given in the table.

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fpi/fpu Stress Relieved Strand and Wire

Stress Relieved Bar and Low Relaxation Strand and Wire

0.80 1.28 0.79 1.22 0.78 1.16 0.77 1.11 0.76 1.05 0.75 1.45 1.00 0.74 1.36 0.95 0.73 1.27 0.90 0.72 1.18 0.85 0.71 1.09 0.80 0.70 1.00 0.75 0.69 0.94 0.70 0.68 0.89 0.66 0.67 0.83 0.61 0.66 0.78 0.57 0.65 0.73 0.53 0.64 0.68 0.49 0.63 0.63 0.45 0.62 0.58 0.41 0.61 0.53 0.37 0.60 0.49 0.33

TABLE 3.4.4-3 STRESS RELAXATION CONSTANT C

For values of fpi/fpu outside of what is given in this table, the following is assumed:

Stress-relieved strand and wire:

For 0.00 < (fpi/fpu) < 0.60, C = linear between 0 and 0.49For 0.75 < (fpi/fpu) < 0.95, C = 1.75

Stress-relieved bar and low-relaxation strand and wire:For 0.00 < (fpi/fpu) < 0.60, C = linear between 0 and 0.33For 0.80 < (fpi/fpu) < 0.95, C = 1.36

These values are extrapolations to provide a rough estimate of losses. Values of fpi/fpu > 0.95 will generate an error message during program execution.

3.4.5 DESCRIPTION OF PRINTOUT

This section describes the printout, data block 16 of the Result Report. The printoutis for the beam shown in Fig. 3.4.5-1.

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16 - FRICTION, ELONGATION AND LONG TERM STRESS LOSSES ==============================================================================

16.2 FRICTION AND ELONGATION CALCULATIONS

16.2.1 INPUT PARAMETERS : Coefficient of angular friction (meu)................ .07000 /radian Coefficient of wobble friction (K)................... .00140 /ft Ratio of jacking stress to strand's ultimate strength .80 Anchor set .......................................... .25 inch Cross-sectional area of strand ...................... .153 inch^2 Modulus of elasticity of strand ..................... 29000.00 ksi STRESSING ........................................... AT BOTH ENDS

16.2.2 CALCULATED STRESSES :

LENGTH < TENDON HEIGHT in.> Horizontal ratios <- STRESS (ksi) --> SPAN ft P start center right X1/L X2/L X3/L start center right -1----2-----3----4------5------6-------7----8----9--------10------11------12- 1 64.00 2 23.00 3.25 31.00 .03 .50 .03 185.85 197.87 190.85 2 55.00 2 31.00 3.25 31.00 .04 .50 .00 189.80 192.85 190.12 3 17.00 2 31.00 22.00 23.00 .00 .50 .06 190.12 182.52 179.60 -------------------------------------- 136.00 ft (total length of tendon) Note: P = tendon type (refer to legend of data block 9) Stresses are after anchor set, but before long-term losses

16.3 SUMMARY : Average initial stress (after release).............. 190.57 ksi Long term stress losses ............................ .00 ksi Final average stress ............................... 190.57 ksi Final average force in tendon ...................... 29.16 k Anchor set influence from left pull ( 200.62ksi).. 38.60 ft Anchor set influence from right pull ( 197.65ksi).. 33.79 ft

Elongation at left pull ............................ 10.322 inch Elongation at right pull ........................... .402 inch Total elongation ................................... 10.725 inch Note: Elongations are all after anchor set

16.4 CRITICAL STRESS RATIOS : At stressing .80; At anchorage .69; Max along tendon .74

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FIGURE 3.4.6.1-1

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Block 16.1 shows the long-term stress losses. The ‘INPUT PARAMETERS’ sectionshows the values input during data entry. The bottom part shows the total long-termlosses as well as the values calculated for elastic shortening, shrinkage, creep andrelaxation. For typical designs, total long-term losses are generally between 11 and13 ksi. They may be somewhat higher for beams with very high averageprecompression.

Block 16.2 shows the friction loss calculations. The ‘INPUT PARAMETERS’section shows the values input during data entry. This is followed by a table whichshows the tendon profile in each span (column 3), the heights at the control points(columns 4 through 6) and the horizontal distance ratios (columns 7 through 9). Thecalculated stresses in the tendon are shown in columns 10 through 12 for the left,center and right of each span.

Block 16.3 gives the average initial stress, the total long-term losses, the final averagestress and the final average force. It also gives the left and right anchor set influencedistances (XL and XR). The numbers in parentheses are the maximum stresses in thetendon; these occur at distances XL and XR (see Fig. 3.4.2-1(f)). The bottom sectionshows the left, right and total elongation after anchor set.

Block 16.4, the Critical Stress Ratios, shows the ratios of the stresses to the strand’sspecified ultimate strength. These should be compared with the maximum permis-sible ratios given in ACI 318.

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3.4.6 NOTATION

a = Anchor set;A = cross sectional area;

CR = stress loss due to creep;

e = eccentricity of tendon from centroidal axis;E

c= concrete’s modulus of elasticity at 28 days;

Eci

= concrete’s modulus of elasticity at stressing age;ES = stress loss due to elastic shortening;E

s= strand’s modulus of elasticity;

fcds

= stress in concrete at center of gravity of tendons due to all superim-posed permanent dead loads that are applied to the member after it hasbeen prestressed;

fcir

= net stress in concrete at center of gravity of tendons immediately afterprestress has been applied to concrete;

fcpa

= average compressive stress in concrete immediately after stressing, at ahypothetical location defined by the center of gravity of tendons;

fpi

= stress in tendon immediately after transfer of prestressing;f

pu= ultimate strength of strand;

I = moment of inertia;J = a coefficient for stress relaxation in tendon (Table 4.3-1);

K = wobble coefficient of friction expressed per unit length of strand;K

cir= an adjustment coefficient for loss due to elastic shortening;

Kcr

= creep coefficient;K

es= a coefficient for elastic shortening stress loss calculation;

Kre

= a coefficient for stress relaxation in tendon;K

sh= a shrinkage constant (Table 4.3-1);

M = moment;

Px

= stress at distance x from the jacking point;

RE = stress loss due to relaxation of tendon;RH = relative humidity (percent);

SH = stress loss due to shrinkage of concrete;

V/S = volume to surface ratio;

X = distance from the stressing point;

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Yb

= centroidal axis to bottom fiber;Y

t= centroidal axis to top fiber;

a = change of angle in strand (radians) from the stressing point to distanceX; and,

m = coefficient of angular friction.

3.5 USER STRESS COMBINATION

This post-processing option allows the user to obtain graphical distributions of stresses forany user specified combination of dead, live and prestressing actions. The results can beviewed on the Stress Results graph by checking the ‘User Combination’ box at the left side ofthe screen.

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A.1 REFERENCES

Aalami, Bijan, Moment-Rotation Relation Between Column and Slab, ACI Journal,Proceedings, V. 69, No. 5, May 1972, pp. 263-269.

Aalami, B. and Barth, F., Restraint Cracks and Their Mitigation in Unbonded Post-TensionedBuilding Structures, American Concrete Institute SP113, 1989, pp. 157-179.

AASHTO, Standard Specifications for Highway Bridges, The American Society of StateHighway and Transportation Officials, Twelfth Edition, 1977.

ACI, Building Code Requirements for Reinforced Concrete, publication, ACI 318-89, 1989.

ACI Committee 443, Prestressed Concrete Bridge Design, Journal, American ConcreteInstitute, Vol. 73, November 1976, pp. 597-612.

Burns, Ned H., Helwig, Todd, and Tsujimoto Tetsuya, Effective Prestress Force in Continu-ous Post-Tensioned Beams with Unbonded Tendons, ACI Structural Journal, January-Febru-ary 1991, pp. 84-90.

Mehrain, Mehrdad, and Aalami, Bijan, Rotational Stiffness of Concrete Slabs, ACIJournal, Proceedings, September 1974, pp. 429-435.

PCI Committee on Prestress Losses, Recommendations for Estimating Prestress Losses,Journal, Prestressed Concrete Institute, July-August 1975, pp. 44-75.

Post-Tensioning Institute, Newsletter, Monthly newsletter, January 1982, p. 4.

Vanderbilt, M. Daniel, and Corley W. Gene, Frame Analysis of Concrete Buildings, ACI,Concrete International, December 1983, pp. 33-43.

Zia, P., Preston, H.K., Scott, N.L. and Workman E.B., Estimating Prestress Losses, Journal,Concrete International, June 1979, pp. 32-38.

adapt-pt · this publication is a supplement to adapt-pt program manual for the analysis and design...

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