design of multi level car park using pre- cast/pre...

R. V. College of Engineering, Bengaluru-560059

(An Autonomous Institution affiliated to VTU, Belgavi)

Department of Civil Engineering

DESIGN OF MULTI LEVEL CAR PARK USING PRE-

CAST/PRE-STRESSED CONCRETE

PROJECT REPORT

Submitted by

NAME OF THE CANDIDATE USN

Uma Maheshwar Reddy S 1RV11CV036

Under the guidance of

Dr. Ravindra R. (Internal Guide)

Associate Professor,

Department of Civil Engineering, RV College Of Engineering, Bengaluru

&

Arjun M.V (External Guide)

General Manager,

TRC Engineering (I) PVT LTD., Bengaluru

In partial fulfilment for the award of degree

Bachelor of Engineering

in

Civil Engineering

2015

R.V. COLLEGE OF ENGINEERING, BENGALURU - 560059

(Autonomous Institution Affiliated to VTU, Belagavi)

DEPARTMENT OF CIVIL ENGINEERING

CERTIFICATE

Certified that the project work titled „Design of Multi-Level Car Park using Pre-Cast/Pre-

Stressed Concrete‟ is carried out by Uma Maheshwar Reddy (1RV11CV036) who is a

bonafide student of R.V College of Engineering, Bangalore, in partial fulfilment for the

award of degree of Bachelor of Engineering in Civil Engineering of the Visvesvaraya

Technological University, Belagavi during the year 2014-2015. It is certified that all

corrections/suggestions indicated for the internal assessment have been incorporated in the

report deposited in the departmental library. The project report has been approved as it

satisfies the academic requirements in respect of project work prescribed by the institution for

the said degree.

Signature of Guide Signature of Head of the Department Signature of Principal

External Viva

Name of Examiners Signature with date

1

2

R.V COLLEGE OF ENGINEERING, BENGALURU-560059

(Autonomous Institution Affiliated To VTU, Belagavi)

DEPARTMENT OF CIVIL ENGINEERING

DECLARATION

I, Uma Maheshwar Reddy S, the student of eighth semester B.E, Civil

Engineering, hereby declare that the project titled “DESIGN OF MULTI-

LEVEL CAR PARK USING PRE-CAST/PRE-STRESSED CONCRETE”

has been carried out by me and submitted in partial fulfilment for the award of

degree of Bachelor of Engineering in Civil Engineering. I do declare that this

work is not carried out by any other student for the award of degree in any other

branch.

Place: Bangalore Names Signature

Date: 1. Uma Maheshwar Reddy S

ACKNOWLEDGEMENT

I would like to express my deepest gratitude to my guide Dr. Ravindra R, Associate

Professor, faculty of Civil Engineering Department, RVCE, Bangalore for efficiently guiding

me throughout the project with his years of experience.

I would also like to express my deepest appreciation for my co-guide Mr Arjun M.V,

General Manager, TRC Engineering (I) PVT LTD. and Dr R. Ravindra, for their

invaluable guidance, advice, suggestions and encouragement, rendered at every stage in my

project work.

I would like to thank Mr. B.M Sagar for helping me in getting this internship.

I am grateful to Dr B.C. Udayashankar, Professor and Head, Department of Civil

Engineering, RVCE for encouraging the project.

I am grateful to our honourable Principal, Dr B.S.Satyanarayana for giving me the

permission to conduct this project.

I am deeply indebted to all the faculty members of Department of Civil Engineering, RVCE

for their knowledge advice and encouragement throughout the course of study.

Above all I wish to express my heartfelt thanks to the almighty GOD, for giving me an

opportunity to do this course.

DESIGN OF MULTI-LEVEL CAR PARK

ABSTRACT

With the rising number of vehicular population along with the city’s growth and rise in per

capita income, high volumes of vehicular traffic and congestion is presently the focus for

attention in most metropolitan cities across the world. A consequence to the inflation in the

traffic scenario, i.e. number of vehicles in cities & unplanned urbanization has led to

congestion. Hence, a decongestion programme backed by a systematic development plan in

basic infrastructure is required. One of the solutions to decongest roads and solve parking

problems is to adopt a multi‐level car parking system to maximise car parking capacity by

utilising vertical space, rather than expanding horizontally. Hence, in this project precast/pre-

stress concrete which are produced by casting concrete in a reusable mold and then cured in a

controlled environment, transported to the construction site and lifted into place using cranes

and connected using various connections for Structural Integrity has been adopted for

structurally designing a Multi-Level Car Park. This parking structure consists of four levels

of parking with two bays of ramp and is situated at Albany, New York. Except for the ground

floor, which is Cast in Situ, every other structural member used for the construction of the

building is made up of pre-cast/pre-stressed concrete.

The following methodology is adopted for this project. Firstly, the lateral loads and vertical

loads acting on the structure are assessed using STRUWARE Code Search. Then the

structure was modelled and analysed for lateral loads such as earthquake, wind loads, etc.

using ETABS. After the structure has satisfied the requirements for lateral loads, the gravity

load bearing members such as Double-Tee beams, Inverted-Tee beams, Spandrels, Columns

and Shear Walls are designed using PRESTO and VERTEX. Finally, the drawings are

prepared and assessed for conformity with accepted standards.

All the individual elements of the parking structure were successfully designed for lateral and

veertical forces and moments acting on them. Furthermore, the connections required to

develop the structural integrity of the parking garage were designed and analysed. Finally, the

parking garage was designed successfully conforming to accepted standards and deemed safe

for use for the purpose of parking vehicles.

Keywords: Precast concrete, Connections, Pre-stressed concrete, Lateral Analysis.

CONTENTS

List of Symbols, Abbreviations and Nomenclature i-ii

List of Tables iii-iv

List of Figures v-vii

Chapter-1 Introduction 01-08

1.1 Preamble. 01

1.2 Applications of Pre-Cast and Pre-Stressed Concrete. 02

1.1.1 Parking Structures 02

1.1.2 Bridges 03

1.1.3 Building Structures 03

1.3 Materials used in Pre-Cast and Pre-Stressed Concrete. 04

1.3.1 Cement 04

1.3.2 Concrete 04

1.3.3 Steel 04

1.4 Literature Review 05

1.5 Motivation 07

1.6 Objective 08

1.7 Methodology 08

1.8 Organisation of Dissertation. 08

Chapter-2 Theory and Fundamentals 09-22

2.1 Analysis of Pre-Cast/Pre-Stressed Structures 09

2.1.1 Gravity Loads 09

2.1.1.1 Dead Loads 09

2.1.1.2 Live Loads 09

2.1.1.3 Snow Loads 10

2.1.2 Lateral Loads 11

2.1.2.1 Wind Loads 11

2.1.2.1.1 ASCE 7-05[2] Method 11

2.1.2.2 Earthquake Loads. 13

2.1.2.2.1 Equivalent Lateral Force Method 14

2.2 Pre-Cast Products 18

2.2.1 Double Tee Beams 19

2.2.2 Spandrel Beams 19

2.2.3 Shear Walls 20

2.2.4 Columns 21

2.2.5 Inverted Tee Beams 21

2.3 Description of Parking Structure 22

Chapter-3 Objectives and Methodology 25-27

3.1 Objectives 25

3.2 Outlines of Methodology 25

3.3 Preparation of Design Criteria using STRUWARE Code Search 26

3.3.1 Codes & Standards 26

3.3.2 Expected Results from STRUWARE Code Search 26

3.4 Lateral Analysis of Structure using ETABS Software. 26

3.5 Overturning Analysis of Shear Wall. 27

3.6 Diaphragm Analysis. 27

3.7 Typical Connection Designs. 27

3.8 Gravity Analysis of Pre-Cast Components. 27

3.9 Preparation of Design Drawings. 27

Chapter-4 Lateral Analysis of Parking Garage 28-74

4.1 ETABS Output 30

4.2 Overturning Analysis 56

4.2.1 Tabulation of Results 56

4.2.2 Overturning Analysis for Walls in X-Direction. 58

4.2.2.1 PDL Calculation 59

4.2.2.2 Overturning Analysis 59

4.2.3 Overturning Analysis for Walls in Y-Direction. 60

4.2.3.1 Overturning Analysis for Shear Wall along Grid‘2’ 60

4.2.3.1.1 PDL Calculation. 61

4.2.3.1.2 Overturning Analysis. 62

4.2.3.1.3 Calculation of Reinforcement. 62

4.2.3.2 Overturning Analysis for Shear Wall along Grid‘4’ 63

4.2.3.2.1 PDL Calculation. 64

4.2.3.2.2 Overturning Analysis. 65

4.2.3.2.3 Calculation of Reinforcement. 65

4.3 Diaphragm Analysis 65

4.3.1 Tabulation of Results 66

4.3.2 Analysis 67

4.3.2.1 Diaphragm Analysis in N-S Direction 69

4.3.2.2 Diaphragm Analysis in E-W Direction. 70

4.3.2.2.1 Diaphragm Analysis (#1 & #2) 71

4.3.2.2.2 Diaphragm Analysis (#3 & #4) 73

Chapter-5 Design of Connections 75-85

5.1 Design of Foundation Connections 75

5.1.1 Design of Column Foundation Connection for Column 24’*34’ 75

5.1.2 Design of Shear Wall Foundation Connection 78

5.1.2.1 Design of Shear Wall Foundation Connection at Grid ‘2’ 78

5.1.2.2 Design of Shear Wall Foundation Connection at Grid ‘4’ 80

5.2 Design of Double-Tee Shear Wall Connection. 82

Chapter-6 Gravity Analysis of Pre-Cast/Pre-Stressed Components 86-117

6.1 Design of Double-Tee Beam Sections using Presto 86

6.1.1 Design of Double-Tee Beam Sections for End Conditions 86

6.1.2 Design of Double-Tee Beam Sections for Interior Conditions 90

6.2 Design of Inverted-Tee Beam Sections using Presto 95

6.2.1 Design of Inverted-Tee Beam Sections using Presto 95

6.3 Design of Spandrel Beam Sections using Presto 100

6.4 Design of Columns Sections using Vertex 103

6.5 Design of Shear Wall Sections using Vertex 106

6.6 Design of Lite Wall Sections using Vertex 111

Chapter-7 Conclusions 118

References 119-121

Annexures 122-127

DESIGN OF MULTI LEVEL CAR PARK

i

LIST OF SYMBOLS, ABBREVIATIONS AND NOMENCLATURES

AB : Area of base of structure, ft2

Ai : Web area of shear walls i, ft2

As : Tension Reinforcement, ft2.

b : Width of Design Section.

Cd : Deflection Amplification Factor.

Ce : exposure factor.

Cplee : Leeward Coefficient.

Cpwind : Windward Coefficient.

Cs : Seismic response coefficient.

Ct : Thermal factor.

CS : Seismic Response Coefficient

d : Depth to Flange Steel

Di : Length of shear wall i, ft.

Fa : Site Coefficient.

f'c : Concrete Strength. .

ft : Mesh Steel Yield Strength.

Fv : Site Coefficient.

G : Gust Effect Factor.

hi : Height of shear wall i, ft.

Ι : Importance factor.

Kd : Directionality Factor.

Kzt : Topographical Factor.

KZT : topographic factor.

Lc : Length of Cantilever

MOT : Over Turning Moment.

MR : Resisting Moment.

P : Concentrated Load.

Pg : Ground snow load, lb./ft2, from Design Aid 4.11.2, 4.11.3(a)[1], or as specified by local

authorities.

Ps : Combined windward and leeward net pressures.

Pf : Flat roof snow load, lb./ft2.

Ps30 : Wind pressure for exposure B at h = 30 ft.


ii

qz : Velocity Pressure .

R : Response Modification Factor.

Ss : Mapped MCE Spectral Response Acceleration.

S1 : Mapped MCE Spectral Response Acceleration.

SMS : MCE Spectral Response Acceleration.

SM1 : MCE Spectral Response Acceleration.

SDS : Design Spectral Response Acceleration,

SD1 : Design Spectral Response Acceleration.

S : Distance between Stems.

tf : Thickness of Precast Flange.

Tl : Long-Period Transition Period.

V : Basic Wind Speed.

V : Seismic Base Shear.

Vu : Shear Force.

W : total dead load of structure.

WLL : Distributed Live Load.

WSL : Distributed Snow Load.

Wt : Weight of Precast Flange Concrete.

x : number of shear walls in the building effective in resisting lateral forces in the direction

under consideration.

zg : Gradient Height.

θ : Influence Angle

Φ : Strength Reduction Factor.

Ωo : System Overstrength Factor.

α : Empirical Exponent.

λ : Height and exposure adjustment factor.


iii

LIST OF TABLES

Table 4.1 Load combination used for modelling...........................................................................29

Table 4.2 Story Data......................................................................................................................31

Table 4.3 Grid Systems................................................................................................................. 31

Table 4.4 Grid Lines......................................................................................................................32

Table 4.5 Material Properties - Summary..................................................................................... 32

Table 4.6 Frame Sections - Summary............................................................................................33

Table 4.7 Shell Sections - Summary..............................................................................................33

Table 4.8 Load Patterns.................................................................................................................34

Table 4.9 Auto Wind - ASCE 7-05 (Part 1 of 2)...........................................................................34

Table 4.10 Auto Wind - ASCE 7-05 (Part 1 of 2).........................................................................34

Table 4.11Applied Story Forces in X-Direction and Y-Direction................................................ 36

Table 4.12 Auto Seismic - ASCE 7-05 (Part 1 of 3)......................................................................37



Table 4.15 Calculated Base Shear along direction-X.....................................................................39

Table 4.16 Lateral Loads along direction-X..................................................................................40

Table 4.17 Calculated Base Shear along direction-Y.....................................................................42

Table 4.18 Lateral Loads along direction-Y..................................................................................43

Table 4.19 Calculated Base Shear along direction X+Ecc Y........................................................45

Table 4.20 Lateral Loads along direction-X + Ecc Y....................................................................46

Table 4.21 Calculated Base Shear along direction X - Ecc Y........................................................48

Table 4.22 Lateral Loads along direction-X -Ecc Y......................................................................49

Table 4.23 Calculated Base Shear along direction Y + Ecc X.......................................................51

Table 4.24 Lateral Loads along direction Y+Ecc X.......................................................................52

Table 4.25 Calculated Base Shear along direction Y - Ecc X........................................................54

Table 4.26 Lateral Loads along direction Y-Ecc X........................................................................55

Table 4.27 Shear Loads on lite wall P2..........................................................................................56

Table 4.28 Shear Loads on lite wall P3..........................................................................................56

Table 4.29 Shear Loads on shear wall P1......................................................................................56

Table 4.30 Shear Loads on shear wall P4......................................................................................57

Table 4.31 Lite Wall Lateral Foundation Forces...........................................................................57

Table 4.32 Shear Wall Lateral Foundation Forces.........................................................................57


iv

Table 4.33 Story Shear for North-South Direction........................................................................66

Table 4.34 Story Shear for East-West Direction............................................................................67

Table 4.35 Comparisons between Lateral Analysis Story Shear and IBC Story Shear for N-S

Direction........................................................................................................................................68

Table 4.36 Comparisons between Lateral Analysis Story Shear and IBC Story Shear for E-W

Direction........................................................................................................................................68

Table 5.1 Strength of bolts and Threaded fasteners.......................................................................77

Table 5.2 Equivalent Area of Corresponding Steel Bars...............................................................81

Table 5.3 Shear Loads in kips for each Shear walls at Corresponding Floor Levels for Shear Wall

at grid ‘2’........................................................................................................................................82

Table 5.4 Shear Loads in kips for each Shear walls at Corresponding Floor Levels for Shear Wall

at grid ‘4’........................................................................................................................................82

Table 6.1 Shear forces for various Pier Labels..............................................................................96

Table 6.2 Reaction from DT stem on LB spandrel in Kips..........................................................101

Table 6.3 Loads in Klf..................................................................................................................101

Table 6.4 Loads and Moment on P1 and P2.................................................................................104


v

LIST OF FIGURES

Fig. 1.1 The Walnut Lane Memorial Bridge, Philadelphia, Pa....................................................1

Fig. 1.2 A parking structure made completely of precast/pre-stressed concrete Bridge..............2

Fig. 1.3 Precast concrete proved to be a key element in completing the Arthur Ravenel Jr.

(Cooper River) Bridge in Charleston, S.C....................................................................................3

Fig. 1.4 Architectural precast concrete panels being used as load-bearing elements...................4

Fig. 2.1 Wind pressure zones on typical building elevations......................................................12

Fig. 2.2 Building Motion during an Earthquake..........................................................................13

Fig. 2.3 An isometric view of a building constructed with Pre-Casted product..........................18

Fig. 2.4 Pre-Cast double Tee beams............................................................................................19

Fig. 2.5 A typical L- Shaped spandrel beam................................................................................20

Fig. 2.6 A Pre Cast Spandrel Beam.............................................................................................20

Fig. 2.7 A Typical Shear wall......................................................................................................20

Fig. 2.8 Columns Pocketed with Corbels.....................................................................................21

Fig. 2.9 An Inverted T-Beam.......................................................................................................22

Fig. 2.10 3-D view of the Parking Garage...................................................................................22

Fig. 2.11 Plan of the Garage at Level-2.......................................................................................23

Fig. 2.12 Elevation Along Grid ‘B’.............................................................................................23

Fig. 2.13 Elevation Along Grid ‘2’..............................................................................................24

Fig. 3.1 Methodology of Work....................................................................................................27

Fig. 4.1 Isometric view of the Howard Street Parking Garage....................................................30

Fig. 4.2 Applied forces along direction-X...................................................................................36

Fig. 4.3 Applied forces along direction-X...................................................................................36

Fig. 4.4 Lateral Load in X- Direction…………………………………………………………..40

Fig. 4.5 Lateral Loads along direction-Y.....................................................................................43

Fig. 4.6 Lateral Loads along direction-X + Ecc Y.......................................................................46

Fig. 4.7 Lateral Loads along direction-X - Ecc Y........................................................................49

Fig. 4.8 Lateral Loads along direction Y + Ecc X.......................................................................52

Fig. 4.9 Lateral Loads along direction Y - Ecc X........................................................................55

Fig. 4.10 Elevation of Litewalls..................................................................................................58

Fig. 4.11 Plan of Litewalls..........................................................................................................59

Fig. 4.12 Plan of Shear Wall………...........................................................................................60

Fig. 4.13 Elevation of Shear Wall...............................................................................................61


vi

Fig. 4.14 Elevation of Shear Wall................................................................................................63

Fig. 4.15 Plan of Shear Wall........................................................................................................64

Fig. 4.16 Plan of Diaphragm under consideration in N-S direction............................................69

Fig. 4.17 Bending Moment and Shear Force Diagrams for Diaphragm in N-S direction...........70

Fig. 4.18 Plan of Diaphragm (#1 & #2).......................................................................................71

Fig. 4.19 Bending Moment and Shear Force Diagrams for Diaphragm (#1 & #2) in E-W

direction…………........................................................................................................................72

Fig. 4.20 Plan of Diaphragm (#3 & #4).......................................................................................73


direction……………………………………………………………………………………........74

Fig. 5.1 Plan and Section of Column-Foundation Connection.....................................................76

Fig. 5.2 Section of Shear Wall-Foundation Connection..............................................................79

Fig. 5.3 Section of Double-Tee to Shear Wall Connection..........................................................83

Fig. 5.4 Embed Plate in Double-Tee............................................................................................84

Fig. 5.5 Embed Plate in Shear Wall.............................................................................................85

Fig. 5.6 Strap Plate for Insert.......................................................................................................85

Fig. 6.1 Load Distributions at the cantilever portion of the Double-Tee.....................................87

Fig. 6.2 Load Distributions at the stem portion of the Double-Tee.............................................88

Fig. 6.3 Load Distributions at the cantilever portion of the Double-Tee.....................................91

Fig. 6.4 Load Distributions at the stem portion of the Double-Tee.............................................93

Fig. 6.5 ITB Load Layout............................................................................................................95

Fig. 6.6 C/S at A-A......................................................................................................................95

Fig. 6.7 Ledge of Inverted-Tee Beam…………………………………………………………..97

Fig. 6.8 Loads acting on the Spandrel………………………………………………………….100

Fig. 6.9 C/S of the given spandrel..............................................................................................100

Fig. 6.10 Loading Diagram........................................................................................................103

Fig. 6.11 Section A-A................................................................................................................103

Fig. 6.12 Cross Section of Column............................................................................................104

Fig. 6.13 Shear Wall along Grid B2 and B4...............................................................................107

Fig. 6.14 12” Shear Wall............................................................................................................108

Fig. 6.15 Line Diagram of Column, h=5’...................................................................................109

Fig. 6.16 Lite Wall Elevation for LW's along grids 'B' between grids '3' and '4'........................112

Fig. 6.17 Line Diagram of Column, h=6’...................................................................................113


vii

Fig. 6.18 Line Diagram of Column, h=6’....................................................................................115

Fig. 6.19 Line Diagram of Column, h=6’....................................................................................116

Design of Multi Level Car Park

Dept. Of Civil Engineering, R.V.C.E Page 1

CHAPTER 1

INTRODUCTION

1.1 PREAMBLE

The growth of precast and pre-stressed concrete is a story of the vision and daring of a few

notable people. Many engineers and scientists took this idea and maximized its potential by

modifying and improving existing methods, conceiving new methods, and inventing new

devices, all with a focus on mass production.

In 1886 Jackson of San Francisco used this idea for construction of artificial stone and concrete

pavements. The most important event leading to the launching of the precast/pre-stressed

concrete industry in North America was the construction in 1950 of the famed Walnut Lane

Memorial Bridge in Philadelphia, Pa. (Fig. 1.1). From technical and historical perspectives, it is

both surprising and fascinating that the Walnut Lane Memorial Bridge was constructed of pre--

stressed concrete. There was very little published information on the subject and there was a total

lack of experience with linear pre-stressing in this country at that time. Furthermore, the length of

the bridge span (the main span of the structure was 160 ft. long) involved would have been a

daring venture in the late 1940s anywhere in the world. The bridge became a reality through a

fortunate sequence of events and the vision, courage, and persistence of few extraordinary

individuals and since then its use has increased immensely around the world.

Fig. 1.1 The Walnut Lane Memorial Bridge, Philadelphia, Pa. [1]



The 1950s were the years that brought into focus the seven-wire strand, long-line beds,

admixtures, high-strength concrete, vacuum concrete, steam curing, and many other innovations.

With these developments, coupled with the technical and logistical support the industry grew,

and the applications of precast and prestressed concrete began to appear in an impressive variety

of structures.

1.2 APPLICATIONS OF PRE-CAST AND PRE-STRESSED CONCRETES

Pre-cast and pre-stressed concrete have tremendous scope for application in the construction

industry and their usage is only going to proliferate with time. Some of the applications of pre-

cast and pre-stressed concrete is given below.

1.2.1 Parking Structures

Architects, engineers, developers, and owners have made precast and prestressed concrete the

material of choice for their commercial, municipal, and institutional parking needs. Though

classified and constructed as buildings, parking structures are unique; in some ways, they may be

compared with bridges with multiple decks. They are subjected to moving loads from automobile

traffic, and the roof level of a parking structure is exposed to weather in much the same way as a

bridge deck. They are subjected to moving loads from automobile traffic. In addition, they are

usually open-air structures and, thus, the entire structure is subjected to ambient weather

conditions, hence it requires special consideration of durability to ensure long-term performance.

An example of a parking structure is shown in Fig. 2.

Fig. 1.2 A parking structure made completely of precast/pre-stressed concrete [1]



1.2.2 Bridges

Bridge construction gave the pre-stressing industry its start in North America. Precast and pre-

stressed concrete is now the dominant structural material for short- to medium-span bridges.

With its inherent durability, low maintenance, performance, and assured quality, precast and pre-

stressed concrete is a natural product for bridge construction. The ability to quickly erect precast

concrete components in all types of weather with little disruption of traffic adds to the economy

of the project. Fig 1.3. Is an example of pre-cast concrete being used as a vital element in the

construction of Arthur Ravenel Jr. (Cooper River) Bridge in Charleston.

Fig. 1.3 Precast concrete proved to be a key element in completing the Arthur Ravenel Jr.

(Cooper River) Bridge in Charleston, S.C.[1]

1.2.3 Building Structures

Owners, developers, and designers recognize the many inherent qualities of precast and pre-

stressed concrete that make it suitable for many types of building structures. Precast and pre-

stressed concrete building structures, assembled from high-quality, plant-produced products,

provide superior flexibility for achieving the required degrees of fire resistance, sound control,

energy efficiency, sustainability, and durability. The availability of various materials and finishes

makes it possible to render almost any desired aesthetic character and hence is used for

architectural works as shown in Fig. 1.4. The speed of construction that is possible with precast



and prestressed concrete minimizes on-site labour costs and reduces the cost of interim financing,

providing important overall economy to the owner and developer.

Fig. 1.4 Architectural precast concrete panels being used as load-bearing elements[1].

1.3 MATERIAL USED IN PRE-CAST AND PRE-STRESSED CONCRETES

1.3.1. Cement: The cement used should be any of the following

(a) Ordinary Portland cement.

(b) Portland slag cement. But the slag content should not be more than 50%.

(c) Rapid hardening Portland cement.

(d) High strength ordinary Portland cement.

1.3.2. Concrete: Pre-stress concrete requires concrete, which has a high compressive strength

reasonably early age with comparatively higher tensile strength than ordinary concrete. The

concrete for the members shall be air-entrained concrete composed of Portland cement, fine and

coarse aggregates, admixtures and water. The air-entraining feature may be obtained by the use

of either air-entraining Portland cement or an approved air-entraining admixture. The entrained

air content shall be not less than 4 per cent or more than 6 per-cent.

Minimum cement content of 300 to 360 kg/m3 is prescribed for the durability requirement. The

water content should be as low as possible.



1.3.3. Steel:-Few types of steel used are high tensile steel, tendons, strands and cables.

The steel used in pre-stress shall be any one of the following:-

(a) Plain hard-drawn steel wire

(b) Cold drawn indented wire

(c) High tensile steel wire bar

(d) Uncoated stress relived strand

High strength steel contains:

0.7 to 0.8% carbons,

0.6% manganese,

0.1% silica

1.4 LITERATURE REVIEW

Lepech et al.[2] discusses the problems arising in the construction industry relating to

sustainability and deterioration of the environment. He has developed a cradle-to-cradle mindset

where infrastructure systems can be designed, built, operated, maintained, reconfigured, and

recycled in a highly sustainable fashion. Through adoption of an integrated design framework for

sustainable infrastructure, durable prefabricated elements can become an important element of

highly sustainable infrastructure systems. Furthermore Lepech et al. discusses the importance of

pre-cast concrete and extols its merits.

Kaar et al. [3] investigated the development of continuity in precast, prestressed concrete bridge

girders used in conventional designs for extending span lengths. The conventional design used

deformed reinforcement in the CIP deck slab over the girders to provide continuity designed for

resisting the live loads. Kaar et al. [3] carried out tests on the connection detail where the

deformed rebar in the deck slab is made continuous over the supports and resists the negative

bending moment. This detail also included the use of a diaphragm over the piers extending

laterally between the girders on either side. The width of the diaphragms was greater than the

spacing between the ends of the girders, which helped to provide lateral restraint to strengthen

the concrete in compression. The results from this study found that this continuity connection

detail was desirable as it permits sufficient redistribution of moment and is simple to construct

and relatively economical.



Mirmiran et al.[4] conducted a research study on positive moment cracking in the diaphragms of

simple-span prestressed girders made continuous. This study was aimed atinvestigating precast

bridge girders that can be made continuous for live loads by providing a moment connection over

the supports. The researchers achieved this by placing negative moment reinforcement in a CIP

deck over the support and by placing a diaphragm between the girder ends. The study also

recommended that ―a minimum amount of positive moment reinforcement equivalent to 1.2Mcr‖

should be used to limit the crack width in the diaphragm and to avoid significant loss of

continuity, where Mcr is the cracking moment of the diaphragm section.

Mattock [5] conducted a study to investigate the accuracy of the fps equation given in ACI 318-

77[6], and proposed an equation, which is currently being used by ACI 318-02[7] and the

AASHTO Standard Specifications, to estimate the stress in the prestressing steel at ultimate

capacity. Mattock related the limit on the maximum amount of tensile steel to the stress in the

prestressing strand at ultimate load and stated that the limit of 0.30 on the reinforcing index is a

good approximation to the point of fps=fpy for low concrete strengths. However, the reinforcing

index corresponding to fps=fpy decreases significantly as the concrete strength increases. Based

on these results, the new limit on the reinforcing index was proposed to be 0.36β1, instead of

0.30. In the 1983 edition of ACI Code (ACI, 1983)[6], the limiting value of 0.30 in ACI 318-

77[6] was changed to 0.36β1 ―so as to account for the effect of increase in concrete strength.

Ronald[8] highlighted the use of a post-tensioning splicing system coupled with high

performance concrete to build longer spans ranging up to 320 ft in Florida. This article focused

on the various factors to be accounted for in the analysis, design, and construction of prestressed,

post-tensioned bulb-tee girders. In this design approach, the bulb-tee girders were precast, pre-

tensioned, and then spliced using post-tensioning performed in two stages on the construction

site. Two types of spliced post-tensioned systems using haunched girder segments over the piers

were discussed in this article. The precast, prestressed bulb-tee girders fabricated in short

segment lengths were spliced on the construction site. Stage 1 post-tensioning allowed for girders

to become continuous before casting of the deck. Stage 2 post-tensioning resulted in residual

compression in the deck for serviceability and deflection control. The two-stage system of post-

tensioning allowed for wider spacing between the girders, and the higher cost of posttensioning

was compensated for by a reduction in the number of piers. The proposed system did not use

intermediate diaphragms. Because lateral stability became an important issue for long and

slender girders, it was recommended to use sections with wide top and bottom flanges. Creep and

shrinkage significantly affect the stress and deflection in continuous composite prestressed



concrete members; therefore, the use of the ultimate creep and shrinkage coefficients in the

analysis was found to be critical. It was recommended to use the coefficients obtained from

previous projects or mix design testing and adjust the girder fabrication and construction

schedules to alleviate the time-dependent effects. The construction process for this spliced

structural system was found to be simple and cost-effective compared to span-by-span and

balanced cantilever construction.

Ng Ban Kiong et al [9]. discuss the factors that will lead to maintenance issues for building using

precast concrete system. These factors will be those that need to be considered at the design,

manufacturing and construction stage for the precast concrete system. Lastly, they also propose

recommendations to be used by designers, contractors, manufacturers and researchers who are

involved in precast concrete system.

A report put forth to the Karnataka government by KSIIDC-IL&FS Project Development

Company (KIPDC)[10], delineates the problems faced due to on road parking as detailed further.

High population density, large number of pavement hawkers, sidewalk encroachments,

heterogeneous nature of traffic and commercial area development along all the major roads have

compounded the problem of congestion on the main as well as internal roads of these cities.

Since there is no planned parking space available within these cities, currently, the city traffic

police allow parking of passenger vehicles on the side of the road thereby eating away a sizeable

portion of motorable road. The precious time of citizens is wasted due to traffic jams and if this

problem is not solved at this stage, and then it would become a serious and complicated problem

in future. Multi‐level parking lots at strategic places and a rational parking fee are inevitable for

solving the problem of finding parking space for the growing number of vehicles.

Jack P. Moehle et al.[11] provides explicit details for the analysis of diaphragm. Furthermore, the

functions of the diaphragm are delineated and different methods of analysis are provided

depending on the state and condition of the diaphragm.

1.5 MOTIVATION

Regular method of in-situ construction is prone to a number of problems such as wastage of

materials, difficulty in controlling the construction phase, susceptibility to large deflections and

cracks due to shrinkage and creep, etc. It has been found that the use of pre-stressed concrete can

negate these drawbacks and offer several other advantages such as improved quality control,

acoustic control, thermal efficiency, etc. Hence, an attempt is made to implement the concept of



pre-stress concrete in the construction of large structures to improve the efficiency of the

construction process.

1.6 OBJECTIVE

The main objective of this project is to understand and implement the concepts of Pre-stressed

and pre-cast concrete in the design of a Multi-Level Car Park for lateral loads (seismic, wind,

etc.), vertical loads (dead load, live load, self-weight, etc.) and design of connections.

1.7 METHODOLOGY

Firstly the plan and the elevation of the parking structure is obtained from the Engineer of Record

(EOR) and the seismic, wind, snow, etc. data is collected pertaining to the location of the parking

structure using a software called STRUWARE code search. After which, the data collected is

used in modelling the parking structure for lateral analysis using ETABS. Then, various

connections were designed for the purpose of connecting various pre-cast elements so as to

achieve structural integrity. Finally, each component is designed for vertical/gravity loads using

PRESTO for horizontal elements and VERTEX for vertical elements.

1.8 ORGANIZATION OF THE DISSERTATION

In this report, in chapter 1 an introduction and history of pre-cast/pre-stressed industry is

delineated. Chapter 2 provides an in-depth explanation of the methods involved in the analysis,

different pre-cast/pre-stressed elements used and the description of the parking structure which is

to be designed. Chapter 3 outlines the methodology adopted in carrying out the project. Chapter 4

contains information regarding lateral analysis of the structure of ETABS which includes

overturning analysis of shear walls and diaphragm analysis. Chapter 5 and Chapter 6 contain

information regarding the design of connections and individual pre-cast elements respectively.

Chapter 8 presents the conclusions of the project and finally the references and annexures are

provided.

***



CHAPTER 2

THEORY AND FUNDAMENTALS

2.1 ANALYSIS OF PRE-CAST/PRE-STRESSED STRUCTRES.

Pre-cast and pre-stressed structures are analysed for various loads such as gravity loads and

lateral loads which are as follows-

1. Gravity Loads

a. Dead Loads

b. Live Loads

c. Snow Loads

2. Lateral Loads

a. Wind Loads

b. Earthquake Loads

2.1.1 GRAVITY LOADS

Gravity loads are generally both live loads and dead loads whose main component is the vertical

force acting on the structure. Typical vertical loads include dead load of the structure, live loads,

loads due to fixed machinery in the building and snow loads. Vertical loads vary in intensity

depending on the type of building, structural materials, height and shape.

2.1.1.1 DEAD LOADS

Dead loads include the self-weight of the structural components plus any materials or elements

that are attached to or permanently in place on the component or assembly. Since the dead loads

are presumed to be determinable with a reasonable degree of accuracy, the load factor by ASCE

7-05[13] is 1.2 when combined with live loads. The ultimate factored load, however, may not be

less than 1.4D when live loads are low.

2.1.1.2 LIVE LOADS

Live loads are considered variable, transient, and not accurately determinable, so the load factor

is higher and is equal to 1.6. In some cases, a maximum live load may be calculated with a high

degree of accuracy (for example, fluid pressure), and a lower load factor is then used.



2.1.1.3 SNOW LOADS

Snow loads are treated differently from other live loads by ASCE 7-05[13] because they are very

transient and vary by geographical location and terrain. The basic snow load for flat roofs is

determined by:

Pf= 0.7CeCtΙPg … (2.1)

Limited by:

Pf≥ ΙpgwherePg≤ 20 lb/ft2

Pf≥ 20Ι where Pg> 20 lb/ft2

where:

Pf= flat roof snow load, lb/ft2

Ce= exposure factor from Design Aid 4.11.3(b)[A1]

Ct= thermal factor from Design Aid 4.11.3(c)[A1]

Ι = importance factor from Design Aid 4.11.1[A2]

Pg= ground snow load, lb/ft2, from Design Aid 4.11.2, 4.11.3(a)[A1], or as

specified by local authorities.

2.1.2 LATERAL LOADS

Most lateral loads are live loads whose main component is horizontal force acting on the

structure. Typical lateral loads would be a wind load against a facade, an earthquake, the wave

pressure against a beach front retaining wall or the earth pressure against a basement wall. Most

lateral loads vary in intensity depending on the building's geographic location, structural

materials, height and shape. The dynamic effects of wind and earthquake loads are usually

analysed as an equivalent static load in most small and moderate-sized buildings. Others must

utilize the iterative potential of the computer.

2.1.2.1 WIND LOADS

The most common lateral load is a wind load. The Eiffel Tower is one example of a building

which has a structure that was designed to resist a high wind load. Wind against a building builds



up a positive pressure on the windward side and a negative pressure (or suction) on the leeward

side. Depending upon the shape of the structure it may also cause a negative pressure on the side

walls or even the roof. The pressure on the walls and roof is not uniform, but varies across the

surface. Winds can apply loads to structures from unexpected directions. Thus, a designer must

be well aware of the dangers implied by this lateral load. The magnitude of the pressure that acts

upon the surfaces is proportional to the square of the wind speed.

There are 3 methods of determining wind loads as per ASCE 7-05[13]:-

Method 1 – Simplified procedure

Method 2 – Analytical procedure

Method 3 – Wind tunnel procedure

In this project only Method 1 is used for the analysis and design for wind loads.

2.1.2.1.1 ASCE 7-05[13] – METHOD 1 FOR WIND DESIGN

The limitations on structures for which this method can be used are generally as follows:

1. Height ≤ 60 ft. or least lateral dimension.

2. Enclosed building (includes parking structures).

3. Regular shaped.

4. No expansion joints.

5. Fundamental frequency H ≤ 1 Hz. (Nearly all concrete buildings under 60 ft. will qualify.)

6. Flat or shallow pitched roof.

The following illustrates the procedures required for this simplified analysis:

1. Determine the basic wind speed from Design Aid 4.11.5[A3].

2. Determine the importance factor Ι from Design Aid 4.11.1[A2].

3. Determine the exposure category that applies to upwind direction.

• Exposure B: Urban and suburban areas, wooded areas

• Exposure D: Flat, unobstructed areas outside hurricane-prone regions



• Exposure C: All others

4. Determine the pressure zones on each side of the building from Fig. 3.1.

5. Determine the height and exposure adjustment factor λ from Design Aid 4.11.6(c)[A4].

6. Determine topographic factor KZT from ASCE 7-05[13].

7. Determine the ps30 forces for each zone from Design Aid 4.11.6(a)[A4].

Fig. 2.1 Wind pressure zones on typical building elevations.[1]

8. The pressure on the MWFRS for each zone is then determined from:

Ps= λKZTΙPs30 … (2.2)

,where:

Ps= combined windward and leeward net pressures

λ = height and exposure adjustment factor

Ι = importance factor

KZT = topographic factor as defined in Section 6.5.7 of ASCE 7-05[13].

Ps30 = wind pressure for exposure B at h = 30 ft.

9. The force on the MWFRS is then determined by multiplying the values of Ps by their

respective zone areas.

ZONE A ZONE B

Width of zone A = the lesser of 20% of the least dimension of the building, or 80% of

the mean roof height, but not less than 8% of the least dimension of the building, or 6 ft. Zone A can be on either end, depending on wind direction.



2.1.2.2 EARTHQUAKE LOADS

Earthquakes generate horizontal and vertical ground movement. When the seismic waves pass

beneath a structure, the foundation will tend to move with the ground, while the superstructure

will tend to remain in its original position. The lag between foundation and superstructure

movement will cause distortions and develop forces in the structure. As the ground moves,

changing distortions and forces are produced throughout the height of the structure. The current

philosophy for the design of earthquake-resistant structures permits minor damage for moderate

earthquakes and accepts major damage for severe earthquakes, provided that the possibility of

complete collapse is minimized. The design details often require large, inelastic deformations to

occur in order to absorb the inertial forces. This is achieved by providing component and

connection ductility. While this ductility can prevent total collapse, the resultant distortions may

lead to significant damage to mechanical, electrical, and architectural elements. Seismic damage

can be minimized by setting limitations on structural deflections, such as interstory drift.

Fig. 2.2 Building Motion during an Earthquake



The response of a structure to the ground motion of an earthquake depends on the structural

system with its damping characteristics and on the distribution of its mass. With mathematical

idealization, a designer can determine the probable response of the structure to an imposed

earthquake. ASCE 7-05[13] requires a dynamic analysis for structures that have highly irregular

shapes or framing systems, or are particularly tall in seismic design categories D, E, and F. While

ASCE 7-05[13] allows a dynamic analysis for other structures, most precast buildings are not tall

and have structural systems and shapes that are more or less regular. Most designers use the

equivalent static force method for these structures.

Different methods of analysing a structure for earthquake loads are as follows:-

1) Time-History Analysis

2) Response Spectrum Analysis

3) Equivalent Lateral Force Method

In this project, only Equivalent Lateral Force Method is adopted and hence, and effort is made to

explain the above mentioned method in detail.

2.1.2.2.1 EQUIVALENT LATERAL FORCE METHOD

The procedure described is applicable to all buildings in seismic design categories B, C, and to

most precast concrete structures in D, E, and F. This method may not apply to buildings with

irregularities in seismic design categories D, E, or F, depending on the nature of the irregularity.

The seismic base shear V in a given direction is determined by:

V = Cs*W … (2.3)

Where:

Cs= seismic response coefficient

W = total dead load of structure plus:

• 25% of floor live load in storage areas (live load in parking structures

not included).

• If partition load is included in gravity load, include the actual partition

weight or a minimum weight of 10 lb./ft2, whichever is greater.



• Total weight of permanent operating equipment.

• 20% of flat-roof snow load where snow load exceeds 30 lb./ft2.

The seismic response coefficient Cs is proportional to the design-response spectrum. The design-

response spectrum has two segments: a short-period plateau and a descending curve with lower

values for longer building periods. Two coefficients, SS and S1, define these two segments, and

they vary with geographical location. Maps of the United States showing contours for SS and S1

are provided in ASCE 7-05[2] and in IBC 2006[4].

To determine Cs:

1. Determine SS and S1 from the map or from local building codes.

2. Determine site classification from soil reports or Design Aid 4.11.7(a)[A5]. If site soils are not

known, use site class D.

3. Calculate response accelerations:

SMS= FaSS … (2.4)

SM1 = FvS1 … (2.5)

Where:

Fa and Fvre site coefficients from Design Aid 4.11.7(b) and

(c)[A5].

4. Calculate the 5% damped design-spectral-response accelerations:

SDS= )SMS … (2.6)

SD1 = (2/3)SM1 … (2.7)

To= (0.2)SD1/ SDS … (2.8)

Ts= SD1/ SDS … (2.9)

5. Determine the seismic design category from Table 4.2.1 of PCI Handbook [1]. This will

sometimes restrict the type of seismic-force-resisting system (SFRS) used.

6. Determine the fundamental period of the building from:



Ta = Cthnx … (2.10)

Where:

Ct = 0.016 for moment-resisting-frame systems of reinforced

concrete in which the frames resist 100% of the required seismic

forces and are not enclosed or adjoined by more rigid components

that prevent that frame from deflecting when subjected to seismic

forces

= 0.020 for other concrete structural systems

hn = distance from base to highest level, ft.

x = 0.9 for concrete moment-resisting frames

= 0.75 for other concrete structural systems

For shear-wall structures, the approximate fundamental period may also be determined from:

√ … (2.11)

Where

∑

(

)

… (2.12)

And

AB= area of base of structure, ft2

Ai = web area of shear walls i, ft2

Di = length of shear wall i, ft.

hi= height of shear wall i, ft.

x = number of shear walls in the building effective in resisting

lateral forces in the direction under consideration.



When designing the lateral-force-resisting system for strength, the period used for the calculation

for the base shear may not exceed the approximate period by more than a factor Cu, which

depends on SD1. The coefficient Cu can be determined from Table 4.2.2 in PCI Handbook [1].

Linear interpolation is permitted for values of SD1 between the values in the table. For shear-wall

buildings, the design period factor may be applied to the longer period value of (2.11) or (2.12).

However, as noted above, the period shall not be taken greater than:

Tmax= CuTa … (2.13)

Cu is found from Table 4.2.2 in PCI Handbook [1].

7. Determine Cs from the lesser of Eq. 2-15 and 2-16 (or 2-17):

Cs= SDS /(R / I) … (2.14)

Where:

R = response modification factor from Design Aid 4.11.8[A6]

I = importance factor from Design Aid 4.11.1[A2]

Cs= SDS /(R / I) for T ≤ TL … (2.15)

Cs = SD1TL/{T2(R / I)}for T >TL … (2.16)

Where:

TL= long-period transition period ASCE 7-05[2]

But cannot be less than:

Cs = 0.044SDSΙ ≥ 0.01 … (2.17)

In addition, for structures located where S1 ≥ 0.6g, Cs cannot be less than:

Cs= 0.5S1/(R / I) … (2.18)

The base shear determined by (2.4) is a function of Cs, which is calculated using (2.15) to (2.19).

Each of these equations has the term R, the response modification coefficient, which is a function

of the lateral-force-resisting system and is provided in Design Aid 4.11.8[A6]. In many cases,

engineering judgement is required to assign the appropriate R. Systems with walls that carry most



of the gravity loads (bearing-wall systems) get lower R factors than systems where structural

walls essentially brace complete gravity frames. This reflects the concern for additional safety

where structural elements that are resisting lateral forces also support gravity loads. Where there

is a gravity system that is independent of the shear walls, but some of the shear walls directly

carry vertical loads to the foundation, the engineer must determine if this creates a bearing-wall

system, or if the building may be defined as a building-frame system that uses shear walls for

lateral-load resistance with the same walls incidentally sharing in part of the vertical support.

Such a system with ordinary, reinforced-concrete shear walls is assigned an R of 5. The

distinction is an important one, because the difference in the R values that are assigned results in

11.1% more lateral load for the bearing-wall system. If the shear walls are truly incidental to the

vertical load frame, then the higher R value is appropriate. It is possible to have different values

of R in two orthogonal directions of the same structure.

2.2 PRE-CAST/PRE-STRESSED PRODUCTS

A blown up, 3-D view of the different types of pre-cast products commonly used in structures is

shown in Fig. 2.3

Fig. 2.3 An isometric view of a building constructed with Pre-Casted product.[1]



2.2.1 DOUBLE TEE BEAMS

A Double Tee beam, used, in construction, is a load-bearing structure of Pre-cast/Pre-stressed

concrete with T-shaped cross section as shown in Fig. 2.4. The top of the T-shaped cross section

serves as a flange or compression member in resisting compressive stresses. The two webs of

the beam below the compression flange serves to resist shear stress and to provide greater

separation for the coupled forces of bending.

Fig. 2.4 Pre-Cast double Tee beams [1]

It provides maximum and resistant use with minimum cross-section size and has less weight so

it‘s easier to transport. They are generally pre-casted in industries, which helps in material

optimisation. This type of beams are generally used in the construction of car parking, extension

of existing bridges, rail bridge decks for short span.

2.2.2 SPANDREL BEAMS

In buildings of more than one story, the spandrel is the area between the sill of a window and the

head of the window below it. Precast spandrel beams are often used on the perimeter of precast

buildings to support the precast floor units. These elements are typically not considered part of

the lateral force resisting system. However, the presence of the spandrel beams in the floor

system may modify the strength, stiffness, and deformation capacity of the precast floor

diaphragm. The nature of this response is highly dependent on the characteristics of the details

connecting the spandrel to the precast floor system [12]. The typical L-shaped spandrel and pre-

cast spandrel is shown in Fig. 2.5 and Fig. 2.6 respectively.

http://en.wikipedia.org/wiki/Construction

http://en.wikipedia.org/wiki/Structural_engineering

http://en.wikipedia.org/wiki/Structure

http://en.wikipedia.org/wiki/Reinforced_concrete

http://en.wikipedia.org/wiki/Reinforced_concrete

http://en.wikipedia.org/wiki/Cross_section_(geometry)

http://en.wikipedia.org/wiki/Flange

http://en.wikipedia.org/wiki/Compression_member

http://en.wikipedia.org/wiki/Compression_(physical)

http://en.wikipedia.org/wiki/Stress_(physics)

http://en.wikipedia.org/wiki/Beam_(structure)

http://en.wikipedia.org/wiki/Shear_stress

http://en.wikipedia.org/wiki/Bending



Fig. 2.5 A typical L- Shaped spandrel beam Fig. 2.6 A Pre Cast Spandrel Beam [1]

2.2.3 SHEAR WALL

In structural engineering, a shear wall is a structural system composed of braced panels (also

known as shear panels) to counter the effects of lateral load acting on a structure. Wind and

seismic loads are the most common loads that shear walls are designed to carry. Shear walls are

vertical elements of the horizontal force resisting system. When shear walls are designed and

constructed properly, they will have the strength and stiffness to resist the horizontal forces. (Fig.

2.7)

Fig. 2.7 A typical Shear wall

Shear walls should be located on each level of the structure including the crawl space. To form

an effective box structure, equal length shear walls should be placed symmetrically on all four

exterior walls of the building. Shear walls should be added to the building interior when the



exterior walls cannot provide sufficient strength and stiffness or when the allowable span-width

ratio for the floor or roof diaphragm is exceeded.

2.2.4 COLUMN

Column or pillar in architecture and structural engineering is a structural element that transmits,

through compression, the weight of the structure above to other structural elements below. In

other words, a column is a compression member. The term column applies especially to a large

round support with a capital and base and made of stone or appearing to be so. A small wooden

or metal support is typically called a post, and supports with a rectangular or other non-round

section are usually called piers. For the purpose of wind or earthquake engineering, columns may

be designed to resist lateral forces. An example of pre-cast column used in a parking structure is

shown in Fig. 2.8.

Fig. 2.8 Columns pocketed with corbels.

2.2.5 INVERTED T-BEAMS

A T-beam is a structural element able to withstand large loads by resistance in the beam or by

internal reinforcements. The upright portion carrying the tension of the beam is termed a web,

and the horizontal part that carries the compression is termed a flange (Fig. 2.9). The T-beam has

a big disadvantage compared to an I-beam because it has no bottom flange with which to deal

with tensile forces. One way to make a T-beam more efficient structurally is to use an inverted T-

http://en.wikipedia.org/wiki/Architecture

http://en.wikipedia.org/wiki/Structural_engineering

http://en.wikipedia.org/wiki/Compression_(physical)

http://en.wikipedia.org/wiki/Pier_(architecture)

http://en.wikipedia.org/wiki/Wind_engineering

http://en.wikipedia.org/wiki/Earthquake_engineering

http://en.wikipedia.org/wiki/I-beam

http://en.wikipedia.org/wiki/Tensile_force



beam with a floor slab or bridge deck joining the tops of the beams. Done properly, the slab acts

as the compression flange.

Fig. 2.9 An Inverted T-Beam

2.3 DESCRIPTION OF PARKING STRUCTURE

The Structure comprises of 4 levels of Parking with 2 bays of Ramp. Apart from the ground floor

and foundation which is cast in place (CIP) all other floors are entirely comprised of pre-cast

elements. It is situated in Albany, New York, USA, the longitudinal coordinates and latitudinal

coordinates of the site is 42o 39’ 16” and 73o 46’ 32”, respectively. It comprises of a

compartment which consists of stair case and an elevator for convenience of the garage users

situated at the north-west and south-east corners of the building. The garage spans 177.6ft in

length, 125.6ft in breath and 57.3ft in height with a distance of 11ft between each floor. The plan

and various elevations are shown through Fig. 2.10-Fig 2.13.

Fig.2.10 3-D view of the Parking Garage.

http://en.wikipedia.org/wiki/Floor_slab

http://en.wikipedia.org/wiki/Bridge_deck



Following building elements were used for construction of the garage:

1. Double Tee Beams

2. Inverted Tee Beams

3. Spandrels

4. Column

5. Shear Walls

6. Lite Walls

Fig. 2.11 Plan of the Garage at Level-2

Fig. 2.12 Elevation Along Grid ‗B‘



Fig. 2.13 Elevation Along Grid ‗2‘

***



CHAPTER 3

OBJECTIVES AND METHODOLOGY

3.1 OBJECTIVES

1. To understand the concepts of Pre-stressed and pre-cast concrete.

2. To analyse and design a structure for lateral loads such as wind loads and seismic loads

and for vertical loads such as dead loads, live loads and snow loads.

3. To design connections so as to transfer load, restrain movement and provide stability.

3.2 OUTLINE OF METHODOLOGY

Fig. 3.1 Methodology of Work.

PREPARATION OF FINAL REPORT.

PREPARATION OF DESIGN DRAWINGS.

GRAVITY ANALYSIS OF PRECAST COMPONENTS.

TYPICAL CONNECTION DESIGNS.

DIAPHRAGM ANALYSIS.

OVERTURNING ANALYSIS OF SHEAR WALLS.

LATERAL ANALYSIS OF THE STRUCTURE USING ETABS SOFTWARE FROM CSI BERKELEY.

PREPARATION OF DESIGN CRITERIA USING STRUWARE CODE SEARCH PROGRAM



3.3 PREPARATION OF DESIGN CRITERIA USING STRUWARE CODE

SEARCH PROGRAM

The loads are assessed and calculated based on the location and relevant codes involved using the

software Struware Code Search. The structure to be designed is located at Albany, New York and

thus, the software uses this information to assess the atmospheric and geological conditions

existing in the area such as seismic zones, wind speed, soil pressure, etc. along with relevant

building codes such as those mentioned in [3.3.1], etc. to calculate the final loads acting on the

building.

3.3.1 CODES AND STANDARDS

1. International Building Code (IBC) 2006 & 2010 New York State Code

2. Minimum Design Loads for Buildings and Other Structures-ASCE 7-05.

3. Building Code requirements of Structural Concrete-ACI 318-05.

4. PCI Design Handbook-Seventh Edition.

3.3.2 EXPECTED RESULTS FROM STRUWARE CODE SEARCH

1. Live Loads

2. Dead Loads

3. Wind Design Data

4. Roof Snow Loads

5. Earthquake Design Data

3.4 LATERAL ANALYSIS OF THE STRUCTURE USING ETABS.

The parking structure is modelled as per the drawings provided by the client for various lateral

loads such as earthquake loads and wind loads using ETABS. The loads acting on the shear walls

and lite walls are determined and are tabulated. These values are then used to carry out

overturning analysis of shear walls as well as diaphragm analysis for the purpose of determining

the stability and integrity of the structure against lateral forces.



3.5 OVERTURNING ANALYSIS OF SHEAR WALLS.

Shear walls act as vertical cantilever beams, which transfer lateral forces acting parallel to the

face of the wall, from the superstructure to the foundation. Shear walls should be oriented to

resist lateral loads applied to the building along both principal axes of the building.

3.6 DIAPHRAGM ANALYSIS

Diaphragms transmit inertial forces from the floor system to the vertical elements of the seismic

force-resisting system. They also tie the vertical elements together and thereby stabilize and

transmit forces among these elements as may be required during earthquake shaking.

Diaphragms are thus an essential part of the seismic force-resisting system and require design

attention by the structural engineer to ensure the structural system performs adequately during

earthquake shaking. [11].

3.7 TYPICAL CONNECTION DESIGNS.

The design of connections is one of the most important considerations in the structural design of

a precast concrete structure. There are many successful solutions to each connection condition.

The purpose of a connection is to transfer load, restrain movement, and/or provide stability.

Within any one connection, there may be several load transfers; each one must be designed for

adequate strength and ductility and be appropriately detailed. The detailing should take into

account allowable tolerances, provide for a good fit between the selected materials, and avoid

interference between strand or reinforcing steel and the connection components, such as headed

concrete anchors or deformed bar anchors.

3.8 GRAVITY ANALYSIS OF PRECAST COMPONENTS.

Each pre-cast member is analyzed and designed according the dead loads, live loads, etc.

prescribed by relevant code books as mentioned in [3.3.1].

3.9 PREPARATION OF DESIGN DRAWINGS.

Sections of the pre-cast members as well as the plan and elevation of the car park are prepared

using AutoCADD.

***



CHAPTER 4

LATERAL ANALYSIS OF THE PARKING GARAGE

Lateral Analysis for the was done using ―ETABS‖ software designed by Computers and

Structures Inc., CA, This program was used mainly to obtain values for the lateral forces resisted

by Lateral force resisting elements, i.e., the structural walls. The program assigns these forces to

the walls/frames based on their relative stiffness and their location within the structure using

mathematical models.

A (3-D) model was created graphically in the program and the structure was analysed for the

effects of wind and seismic forces in accordance with the International Building Code (IBC)

2006 [15] and ASCE 7-05 [13]– Minimum Design Loads for Buildings and Other Structures.

The structure contains 5 levels of parking with 2 bays of Ramps. The extent of Grids is Grid ‗1‘

to ‗5‘at North-South direction and Grids ‗A‘ to ‗C‘ at East-West Direction.

Following are some of the assumptions made to model the structure in ETABS:

1. 12‖ thick Shear walls along Grid ‗2‘ and Grid ‗4‘ of the Structure which are running for entire

height in Global ‗Y‘ (East-West) and 12‖ thick Lite Walls along Grid ‗B‘ which runs for the

entire height in Global ‗X‘ (North-South) directions respectively are considered to be the part of

Lateral resisting system.

2. Some of the walls in the structure were not used as part of the lateral system, however, they

were modelled in order to get the correct mass for the entire structure.

3. The floor members in the Parking area (15DT30s) in the model are assigned with 6.37‖

Thickness which gives it‘s correct self-weight of 79.625 psf.

4. Ramps are modelled ―flat‖ at its upper level in ETABS conservatively.

5. All of the Precast Floors/Roofs as mentioned above are modelled as ―Rigid Diaphragm‖ to

transfer the lateral forces to the lateral resisting elements.

6. The Response Factor, R = 4 for Lite walls & Shear walls.

7. The load combination which was used in modelling is given in Table 4.1 below.



The program calculates and distributes all story shears to the lateral load resisting elements based

on the Stiffness‘s etc. The resulting Base Shears and Overturning Moments have been tabulated

for each of the lateral load resisting elements. The stability of the lateral loads resisting elements

was studied based on the output obtained.

A Quality Control Check was done to ensure that the program has calculated the correct seismic

weight and corresponding total base shear on the structure.

The load combinations used for modelling the structure is displayed in Table 4.1.

Table 4.1 Load combination used for modelling

Type of Load Multiplication Factor Referral Code Book

DL 1.2 ASCE 07-05[13]

LL 1.5 ASCE 07-05[13]

SL 0.2 ASCE 07-05[13]



4.1 ETABS OUTPUT

Fig. 4.1 Isometric wireframe view of the Howard Street Parking Garage

ETABS OUTPUT

HOWARD STREET PG

MULTI LEVEL CAR PARK



4.1.1 STRUCTURE DATA

This chapter provides model geometry information, including items such as story levels, point

coordinates, and element connectivity.

4.1.1.1 STOREY DATA

Table 4.2 - Storey Data

Name Height

(in.)

Elevation

(in.)

STAIR

TOWER 90 1833

5 132 1743

4 132 1611

3 132 1479

2 132 1347

1 159 1215

Base 0 1056

4.1.1.2 GRID DATA

Table 4.3 - Grid Systems

Name Type Story

Range

X

Origin

(Ft.)

Y

Origin

(Ft.)

Rotation

(deg)

G1 Cartesian Default 0 0 0



Table 4.4 - Grid Lines

Grid

System

Grid

Direction Grid ID Visible

Ordinate

(Ft.)

G1 X 1 Yes 0

G1 X 1.2 Yes 11.17

G1 X 2 Yes 42

G1 X 3 Yes 87

G1 X 4 Yes 132

G1 X 4.5 Yes 153.33

G1 X 5 Yes 174

G1 Y C Yes 0

G1 Y C.4 Yes 20.67

G1 Y B Yes 59

G1 Y A.4 Yes 96.5

G1 Y A Yes 118

4.1.2 PROPERTIES

This chapter provides property information for materials, frame sections, shell sections, and

links.

4.1.2.1 MATERIALS

Table 4.5 - Material Properties - Summary

Name Type E

(lb./in²)

Unit

Weight

(lb./ft³)

Design Strengths

A615Gr60 Rebar 29000000 490 Fy=60000 lb./in²,

Fu=90000 lb./in²

PRECAST Concrete 4415201 150 Fc=6000 lb./in²



4.1.2.2 FRAME SECTIONS

Table 4.6 - Frame Sections - Summary

Name Material Shape

10C10 PRECAST Concrete Rectangular

10SP132 PRECAST Concrete Rectangular






32IT36 PRECAST Concrete Rectangular



4.1.2.3 SHELL SECTIONS

Table 4.7 - Shell Sections - Summary

Name Design

Type

Element

Type Material

Total

Thickness

(in.)

15DT30 Slab Membrane PRECAST 6.37

16'' STAIRCASE

SLAB Slab Membrane PRECAST 16

LITE WALLS Wall Shell-Thin PRECAST 12

SHEAR WALL Wall Shell-Thin PRECAST 12



4.1.3 LOADS

This chapter provides loading information as applied to the model.

4.1.3.1 LOAD PATTERNS

Table 4.8 - Load Patterns

Name Type Self- Weight

Multiplier Auto Load

Dead Dead 1

Live Live 0

EQX1 Seismic 0 ASCE 7-05[13]

WIND Wind 0 ASCE 7-05[13]

EQY1 Seismic 0 ASCE 7-05[13]





4.1.3.2 AUTO WIND LOADING

Table 4.9 - Auto Wind - ASCE 7-05 (Part 1 of 2)

Load

Pattern

Loading

Method

Exposure

Width Type

Angle

deg Cp,wind Cp,lee

ASCE

Case Top Story

WINDX Diaphragms From

Diaphragms 0 0.8 0.5 Case 1

Stair

Tower

WINDY Diaphragms From

Diaphragms 90 0.8 0.5 Case 1

Stair

Tower

Table 4.10 - Auto Wind - ASCE 7-05 (Part 2 of 2)

Wind

Speed

mph

Exposure

Type

Importance

Factor

I

Topographica

l Factor

Kzt

Gust Effect

Factor

G

Directionality

Factor

Kd

85 B 1 1 0.85 0.85



4.1.3.3 ASCE 7-05 AUTO WIND LOAD CALCULATION

This calculation presents the automatically generated lateral wind loads for load pattern WIND

according to ASCE 7-05[2], as calculated by ETABS.

Exposure Parameters

Exposure From = Diaphragms

Exposure Category = B

Wind Direction = 0 degrees

Basic Wind Speed, V [ASCE 6.5.4][2]

Windward Coefficient, Cp,wind [ASCE 6.5.11.2.1][2]

Leeward Coefficient, Cp,lee [ASCE 6.5.11.2.1][2]

Wind Cases = All Cases

Top Story = 5A

Bottom Story = Base

Include Parapet = No

Factors and Coefficients

Gradient Height, zg [ASCE Table 6-2][2]

Emperical Exponent, α [ASCE Table 6-2][2]

Topographical Factor, Kzt [ASCE 6.5.7.2] [2]

Directionality Factor, Kd [ASCE 6.5.4.4] [2]

Importance Factor, I [ASCE 6.5.5][2]

Gust Effect Factor, G [ASCE 6.5.8][2]

Lateral Loading

Velocity Pressure, qz [ASCE 6.5.10 Eq. 4-1][2]

Design Wind Pressure, p [ASCE 6.5.12.2.1 Eq. 4-2][2]



Fig. 4.2 Applied Story Forces in X-Direction Fig. 4.3 Applied Story Forces in X-Direction

Table 4.11 Applied Story Forces in X-Direction and Y-Direction

Story Elevation X-Dir Y-Dir

Stair Tower 152.75 0 0

5 145.25 9.39 13.846

4 134.25 18.299 26.983

3 123.25 17.471 25.763

2 112.25 16.425 24.219

1 101.25 0 0

Base 88 0 0



4.1.3.4 AUTO SEISMIC LOADING

Table 4.12 - Auto Seismic - ASCE 7-05 (Part 1 of 3)

Load

Pattern Type Direction

Eccentricity

%

Ecc.

Overridden

Period

Method

User T

sec Top Story

Bottom

Story R

EQX1 Seismic X No User

Specified 0.416

STAIR

TOWER Base 4

EQY1 Seismic Y No User

Specified 0.416

STAIR

TOWER Base 4

EQX2 Seismic X + Ecc. Y 5 No User

Specified 0.416

STAIR

TOWER Base 4

EQX3 Seismic X - Ecc. Y 5 No User

Specified 0.416

STAIR

TOWER Base 4

EQY2 Seismic Y + Ecc. X 5 No User

Specified 0.416

STAIR

TOWER Base 4

EQY3 Seismic Y - Ecc. X 5 No User

Specified 0.416

STAIR

TOWER Base 4


Ω Cd I SS/S1 Source SS S1 Site

Class Fa Fv SDS SD1

2.5 4 1 User Specified 0.229 0.069 D 1.6 2.4 0.244267 0.1104

2.5 4 1 User Specified 0.229 0.069 D 1.6 2.4 0.244267 0.1104

2.5 4 1 User Specified 0.229 0.069 D 1.6 2.4 0.244267 0.1104

2.5 4 1 User Specified 0.229 0.069 D 1.6 2.4 0.244267 0.1104

2.5 4 1 User Specified 0.229 0.069 D 1.6 2.4 0.244267 0.1104

2.5 4 1 User Specified 0.229 0.069 D 1.6 2.4 0.244267 0.1104




Period

Used

(sec)

Co-eff

Used

Weight

Used

(kip)

Base

Shear

(kip)

0.416 0.061067 11748.71 717.455

0.416 0.061067 11748.71 717.455

0.416 0.061067 11748.71 717.455

0.416 0.061067 11748.71 717.455

0.416 0.061067 11748.71 717.455

0.416 0.061067 11748.71 717.455

4.1.3.5 ASCE 7-05 AUTO SEISMIC LOAD CALCULATION

This calculation presents the automatically generated lateral seismic loads for load pattern EQX1

according to ASCE 7-05[2], as calculated by ETABS.

Direction and Eccentricity

Direction = X

Structural Period

Period Calculation Method = User Specified

User Period

Long-Period Transition Period, TL [ASCE 11.4.5][2]


Response Modification Factor, R [ASCE Table 12.2-1][2]

System Overstrength Factor, Ω0 [ASCE Table 12.2-1][2]

Deflection Amplification Factor, Cd [ASCE Table 12.2-1][2]

Importance Factor, I [ASCE Table 11.5-1][2]

Ss and S1 Source= User Specified



Mapped MCE Spectral Response Acceleration, Ss [ASCE 11.4.1][2]

Mapped MCE Spectral Response Acceleration, S1 [ASCE 11.4.1][2]

Site Class [ASCE Table 20.3-1][2] = D - Stiff Soil

Site Coefficient, Fa [ASCE Table 4.3-1][2]

Site Coefficient, Fv [ASCE Table 4.3-2][2]

Seismic Response

MCE Spectral Response Acceleration, SMS

[ASCE 11.4.3, Eq. 4.4-1][2]

MCE Spectral Response Acceleration, SM1

[ASCE 11.4.3, Eq. 4.4-2][2]

Design Spectral Response Acceleration, SDS

[ASCE 11.4.4, Eq. 4.4-3][2]

Design Spectral Response Acceleration, SD1

[ASCE 11.4.4, Eq. 4.4-4][2]

Equivalent Lateral Forces

Seismic Response Coefficient, CS [ASCE 12.8.1.1, Eq. 4.5-2]

[ASCE 12.8.1.1, Eq. 4.5-3][2]

[ASCE 12.8.1.1, Eq. 4.5-5][2]

Calculated Base Shear

Table 4.15 Calculated Base Shear along direction-X

Direction Period Used

(sec) Cs

W

(kip)

V

(kip)

X 0.416 0.061067 11748.7099 717.4545



Applied Story Forces

Fig.4.4 Lateral Load in X- Direction.

Table 4.16 Lateral Load in X- Direction.


Stair Tower 152.75 0 0

5 145.25 9.39 0

4 134.25 18.299 0

3 123.25 17.471 0

2 112.25 16.425 0

1 101.25 0 0

Base 88 0 0




This calculation presents the automatically generated lateral seismic loads for load pattern EQY1

according to ASCE 7-05, as calculated by ETABS.


Direction = Y

Structural Period


User Period







Ss and S1 Source= User Specified

Mapped MCE Spectral Response Acceleration, Ss [ASCE 11.4.1][2]

Mapped MCE Spectral Response Acceleration, S1 [ASCE 11.4.1][2]




Seismic Response


[ASCE 11.4.3, Eq. 4.2-1][2]




[ASCE 11.4.3, Eq. 4.2-2][2]

Design Spectral Response Acceleration,

SDS[ASCE 11.4.4, Eq. 4.2-3][2]

... (4.1)


[ASCE 11.4.4, Eq. 4.2-4][2]

. ... (4.2)


Seismic Response Coefficient, CS [ASCE 12.8.1.1, Eq. 4.3-2][2]

... (4.3)

[ASCE 12.8.1.1, Eq. 4.3-3][2]

... (4.4)

[ASCE 12.8.1.1, Eq. 4.3-4][2]


Table 4.17 Calculated Base Shear along direction-Y


(sec) Cs

W

(kip)

V

(kip)

Y 0.416 0.06106

7

11748.709

9

717.454

5




Fig. 4.5 Lateral Loads along direction-Y

Table 4.18 Lateral Loads along direction-Y


Ft. kip kip

STAIR

TOWER 152.75 0 25.831

5 145.25 0 230.664

4 134.25 0 197.691

3 123.25 0 148.504

2 112.25 0 103.992

1 101.25 0 10.772

Base 88 0 0







Direction = X + Eccentricity Y

Eccentricity Ratio = 5% for all diaphragms

Structural Period


User Period







Ss and S1Source=User Specified

Mapped MCE Spectral Response Acceleration, Ss [ASCE

11.4.1][2]

Mapped MCE Spectral Response Acceleration, S1 [ASCE

11.4.1][2]






Seismic Response


[ASCE 11.4.3, Eq. 4.2-1][2]

... (4.5)

MCE Spectral Response Acceleration,

SM1[ASCE 11.4.3, Eq. 4.2-2][2]

... (4.6)


[ASCE 11.4.4, Eq. 4.2-3][2]

... (4.7)


[ASCE 11.4.4, Eq. 4.2-4] [2]

... (4.8)


Seismic Response Coefficient, CS

[ASCE 12.8.1.1, Eq. 4.3-2]

... (4.9)

[ASCE 12.8.1.1, Eq. 4.3-3] [2]

... (4.10)

[ASCE 12.8.1.1, Eq. 4.3-5] [2]


Table 4.19 Calculated Base Shear along direction X+Ecc Y


(sec) Cs

W

(kip)

V

(kip)

X + Ecc. Y 0.416 0.061067 11748.7099 717.4545




Fig. 4.6 Lateral Loads along direction-X + Ecc Y

Table 4.20 Lateral Loads along direction-X + Ecc Y


Ft. kip kip

STAIR

TOWER 152.75 25.831 0

5 145.25 230.664 0

4 134.25 197.691 0

3 123.25 148.504 0

2 112.25 103.992 0

1 101.25 10.772 0

Base 88 0 0







Direction = X - Eccentricity Y


Structural Period


User Period

Long-Period Transition Period, TL [ASCE 11.4.5] [2]


Response Modification Factor, R [ASCE Table 12.2-1] [2]

System Overstrength Factor, Ω0 [ASCE Table 12.2-1] [2]

Deflection Amplification Factor, Cd [ASCE Table 12.2-1] [2]

Importance Factor, I [ASCE Table 11.5-1] [2]

Ss and S1 Source=User Specified

Mapped MCE Spectral Response Acceleration, Ss [ASCE 11.4.1]

Mapped MCE Spectral Response Acceleration, S1 [ASCE 11.4.1]

Site Class [ASCE Table 20.3-1] [2]= D - Stiff Soil

Site Coefficient, Fa [ASCE Table 11.4-1] [2]

Site Coefficient, Fv [ASCE Table 11.4-2] [2]



Seismic Response


[ASCE 11.4.3, Eq. 4.2-1] [2]

... (4.11)


[ASCE 11.4.3, Eq. 4.2-2] [2]

... (4.12)


[ASCE 11.4.4, Eq. 4.2-3] [2]

... (4.13)


[ASCE 11.4.4, Eq. 4.2-4] [2]

... (4.14)


Seismic Response Coefficient, CS [ASCE 12.8.1.1, Eq. 4.3-2]

... (4.15)

[ASCE 12.8.1.1, Eq. 4.3-3] [2]

... (4.16)

[ASCE 12.8.1.1, Eq. 4.3-5] [2]


Table 4.21 Calculated Base Shear along direction X - Ecc Y


(sec) Cs

W

(kip)

V

(kip)

X - Ecc. Y 0.416 0.061067 11748.7099 717.4545




Fig. 4.7 Lateral Loads along direction-X - Ecc Y

Table 4.22 Lateral Loads along direction-X –Ecc Y


Ft. kip kip

STAIR

TOWER 152.75 25.831 0

5 145.25 230.664 0

4 134.25 197.691 0

3 123.25 148.504 0

2 112.25 103.992 0

1 101.25 10.772 0

Base 88 0 0



4.1.3.9 ASCE 7-05[2] AUTO SEISMIC LOAD CALCULATION

This calculation presents the automatically generated lateral seismic loads for load pattern

EQY2 according to ASCE 7-05[2], as calculated by ETABS.


Direction = Y + Eccentricity X


Structural Period


User Period








Mapped MCE Spectral Response Acceleration, Ss [ASCE 11.4.1] [2]

Mapped MCE Spectral Response Acceleration, S1 [ASCE 11.4.1] [2]

Site Class [ASCE Table 20.3-1] [2]= D - Stiff Soil





Seismic Response


[ASCE 11.4.3, Eq. 4.2-1] [2]

... (4.17)


[ASCE 11.4.3, Eq. 4.2-2] [2]

... (4.18)


SDS [ASCE 11.4.4, Eq. 4.2-3] [2]

... (4.19)


SD1 [ASCE 11.4.4, Eq. 4.2-4] [2]

... (4.20)


Seismic Response Coefficient, CS [ASCE 12.8.1.1, Eq. 4.3-2] [2]

... (4.21)

[ASCE 12.8.1.1, Eq. 4.3-3] [2]

... (4.22)

[ASCE 12.8.1.1, Eq. 4.3-5] [2]


Table 4.23 Calculated Base Shear along direction Y + Ecc X


(sec) Cs

W

(kip)

V

(kip)

Y + Ecc. X 0.416 0.061067 11748.7099 717.4545




Fig. 4.8 Lateral Loads along direction Y + Ecc X

Table 4.24 Lateral Loads along direction Y + Ecc X


Ft kip kip

STAIR

TOWER 152.75 0 25.831

5 145.25 0 230.664

4 134.25 0 197.691

3 123.25 0 148.504

2 112.25 0 103.992

1 101.25 0 10.772

Base 88 0 0



4.1.3.10 ASCE 7-05[2] Auto Seismic Load Calculation

This calculation presents the automatically generated lateral seismic loads for load pattern

EQY3 according to ASCE 7-05[2], as calculated by ETABS.


Direction = Y - Eccentricity X


Structural Period


User Period








Mapped MCE Spectral Response Acceleration, Ss [ASCE 11.4.1] [2]

Mapped MCE Spectral Response Acceleration, S1 [ASCE 11.4.1] [2]

Site Class [ASCE Table 20.3-1] [2] = D - Stiff Soil





Seismic Response


[ASCE 11.4.3, Eq. 4.2-1] [2]

... (4.23)

MCE Spectral Response Acceleration,

SM1[ASCE 11.4.3, Eq. 4.2-2] [2]

... (4.24)


[ASCE 11.4.4, Eq. 4.2-3] [2]

... (4.25)


[ASCE 11.4.4, Eq. 4.2-4] [2]

... (4.26)


Seismic Response Coefficient, CS

[ASCE 12.8.1.1, Eq. 4.3-2]

... (4.27)

[ASCE 12.8.1.1, Eq. 4.3-3] [2]

... (4.28)

[ASCE 12.8.1.1, Eq. 4.3-5] [2]


Table 4.25 Calculated Base Shear along direction Y - Ecc X


(sec) Cs

W

(kip)

V

(kip)

Y - Ecc. X 0.416 0.061067 11748.7099 717.4545




Fig. 4.9 Lateral Loads along direction Y - Ecc X

Table 4.26 Lateral Loads along direction Y- Ecc X


ft kip kip

STAIR

TOWER 152.75 0 25.831

5 145.25 0 230.664

4 134.25 0 197.691

3 123.25 0 148.504

2 112.25 0 103.992

1 101.25 0 10.772

Base 88 0 0



4.2 OVERTURNING ANALYSIS

4.2.1 TABULATION OF RESULTS

WALLS IN (‗X‘ DIRECTION) NORTH-SOUTH DIRECTION

Table 4.27 Shear Loads on lite wall P2

STORY CUM SHEAR (Kips) MOMENT (Kips-ft.)

5 136.406 955.6518

4 219.132 2779.802

3 284.09 5341.158

2 358.869 8834.143

1 360.122 10724.78

Table 4.28 Shear Loads on lite wall P3


5 136.406 955.6518

4 219.132 2779.8018

3 284.09 5341.158

2 358.869 8834.143

1 360.122 10724.784

WALLS IN (‗Y‘ DIRECTION) EAST-WEST DIRECTION

Table 4.29 Shear Loads on shear wall P1


5 145.583 1603.7209

4 250.448 4361.7516

3 324.054 7930.7012

2 416.123 12510.427

1 417.153 15169.779



Table 4.30 Shear Loads on shear wall P4


5 130.678 1436.72

4 195.235 3583.605

3 252.924 6365.844

2 308.047 9753.719

1 309.077 11724.09

Table 4.31 Lite Wall Lateral Foundation Forces

STORY PIER LOAD LOCATION V2(Kips) M3(Kips-ft.)

1 P3 WIND X Bottom 30.973 798.3737

1 P3 EQX1 Bottom 360.182 10724.55

1 P3 EQX2 Bottom 360.242 10724.33

1 P3 EQX3 Bottom 360.122 10724.78

1 P2 WIND X Bottom 30.973 798.3737

1 P2 EQX1 Bottom 360.182 10724.55

1 P2 EQX2 Bottom 360.242 10724.33

1 P2 EQX3 Bottom 360.122 10724.78

Table 4.32 Shear Wall Lateral Foundation Forces

STORY PIER LOAD LOCATION V2(Kips) M3(Kips-ft.)

1 P1 WIND Y Bottom 45.983 1449.4999

1 P1 EQX1 Bottom 348.148 12794.7234

1 P1 EQX2 Bottom 279.143 10419.6677

1 P1 EQX3 Bottom 417.153 15169.7791

1 P4 WINDY Bottom 45.966 1453.5021

1 P4 EQX1 Bottom 378.029 14106.5006

1 P4 EQX2 Bottom 446.981 16488.9157

1 P4 EQX3 Bottom 309.077 11724.0856



4.2.2 OVERTURNING ANALYSIS FOR WALLS IN X-DIRECTION

Assumptions

PDL is the sum of the wall panel self-weight and the DT stem loads (Linear load

multiplied by panel width) from the Foundation Load Summary Sheet.

PDL conservatively acts at the centre of the Wall Panel.

The Tension support is 1.50' from the end.

The compression support is 0.50' from the end.

For all Light Walls, the Lever arm distance to calculate the Tu will be Width of LW' -

(1.50 + 0.5').

Fig. 4.10 Elevation of LITEWALLS



Fig. 4.11 Plan of LITEWALLS

4.2.2.1 PDL Calculation:

Litewall self-weight =43.88' x 49.25'x 1.00' x 0.150 ksf

Deduct openings -4.00' x 6.00' x 1.00' x 0.150 ksf x 20 numbers

=252.1 K klf

DL from Double Tees =45.00' x 59.00' x 0.080 ksf x 4 levels

=849.6 K klf

Total Pdl =252.1 K +849.6 K

=1101.7 K klf

4.2.2.2 Overturning Analysis:

Over Turning Moment, MOT =10724.78 'K

Shear Force , Vu = 360.2 K

Resisting Moment , MR = 1101.7 K x 21.44‘ = 23620.45 'K

Lever Arm, l =43.88

W/Load Combination : 0.85 DL + 1.0 E

Tu = (MOT -0.85 x MR)/l … (4.29)



=

=-213.2 K

4.2.3 OVERTURNING ANALYSIS FOR WALLS IN Y-DIRECTION

Assumptions

PDL is the sum of the wall panel self-weight and the DT stem loads (Linear load

multiplied by panel width) from the Foundation Load Summary Sheet.

PDL conservatively acts at the centre of the Wall Panel.

The Tension support is 1.50' from the end.

The compression support is 0.50' from the end.

For all Light Walls, the Lever arm distance to calculate the Tu will be Width of LW' -

(1.50 + 0.5').

4.2.3.1 OVERTURNING ANALYSIS FOR SHEARWALL ALONG GRID ‘2’

Fig 4.12 Plan of SHEAR WALL

NO UPLIFT!



Fig 4.13 Elevation of SHEAR WALL

4.2.3.1.1 PDL Calculation:

Shear wall self-weight = 30.00‘ x 50.38' x 1.00' x 0.150 ksf

Pilaster self-weight =3.00' x 50.38' x 1.00' x 0.150 ksf

=249.4 K klf

Deduct openings -4.00' x 5.00' x 1.00' x 0.150 ksfx8 numbers



=225.4 K klf

DL from IT-beams =1.09 klf x 22.94' x4 levels

=100.0 K klf


=401.4 K klf

Load from Concrete pad = ((32.0' x 16.0' x 0.075 ksf) x 16.0') / 61.5'

=10.0 K klf

Total Pdl =225.4 K +100.0 K +401.4 K +10.0 K

=736.8 K klf

4.2.3.1.2 Over Turning Analysis:

Over Turning Moment, MOT=15169.78 'K

Shear Force , Vu =417 K

Resisting Moment , MR =760.8 K x 14.50‘ = 11031.60 'K

Lever Arm, l = 28‘


Tension, Tu = (MOT -0.85 x MR)/l … (4.30)

=

= 206.9 ‘K

4.2.3.1.3 Calculation of Reinforcement

Steel Required, As =Tu/Φfy … (4.31)

=206.9/ (0.9*60)

PROVIDE As



=3.831 in2

Number of #11(1.56in2) bars required for the prevention of overturning of shear walls,

=3.831/1.56

=3 Bars

Therefore 3 #11(1.56in2) are required to be provided for the prevention of overturning of

shear walls.

4.2.3.2 OVERTURNING ANALYSIS FOR SHEARWALL ALONG GRID ‘4’

Fig 4.14 Elevation of SHEAR WALL



Fig 4.15 Plan of SHEAR WALL

4.2.3.2.1 PDL Calculation:

Shear wall self-weight = 30.00‘ x 50.38' x 1.00' x 0.150 ksf

Pilaster self-weight =3.00' x 50.38' x 1.00' x 0.150 ksf

=249.4 K klf

Deduct openings -4.00' x 5.00' x 1.00' x 0.150 ksf x8 numbers

=225.4 K klf

DL from IT-beams =1.09 klf x 22.94' x4 levels

=100.0 K klf


=401.4 K klf

Load from Concrete pad = ((32.0' x 16.0' x 0.075 ksf) x 16.0') / 61.5'

=10.0 K klf

Total Pdl =225.4 K +100.0 K +401.4 K +10.0 K

=736.8 K klf

4.2.3.2.2 Over Turning Analysis:

Over Turning Moment, MOT=15169.78 'K

Shear Force , Vu =417 K

Resisting Moment , MR =760.8 K x 14.50‘

= 11031.60 'K

Lever Arm, l =28‘




Tu = (MOT -0.85 x MR)/l … (4.32)

=

= 254 ‘K

4.2.3.2.3 Calculation of Steel Required For the Prevention of Overturning of Shear

Walls

Steel Required, As =Tu/Φfy … (4.33)

=254/ (0.9*60)

=4.704 in2

Number of #11(1.56in2) bars required for the prevention of overturning of shear walls,

=4.704/1.56

=4 Bars

Therefore 4 #11(1.56in2) are required to be provided for the prevention of overturning of

shear walls.

4.3 DIAPHRAGM ANALYSIS

Diaphragms transmit inertial forces from the floor system to the vertical elements of the

seismic force-resisting system. They also tie the vertical elements together and thereby

stabilize and transmit forces among these elements as may be required during earthquake

shaking. Diaphragms are thus an essential part of the seismic force-resisting system and

require design attention by the structural engineer to ensure the structural system performs

adequately during earthquake shaking.[11]

PROVIDE As



4.3.1 TABULATION OF RESULTS

Table 4.33 Story Shear for North-South Direction

STORY LOAD CASE VX

(Kips)

MAX

(Kips)

STORY SHEAR

(Kips)

5 EQX1 -282.326

-282.326 -282.326

5 EQX2 -256.496

5 EQX3 -256.496

5 WIND X -9.39

4 EQX1 -454.186

-454.186 -171.86

4 EQX2 -454.186

4 EQX3 -454.186

4 WIND X -27.689

3 EQX1 -602.69

-602.69 -148.504

3 EQX2 -602.69

3 EQX3 -602.69

3 WIND X -45.16

2 EQX1 -706.683

-706.682 103.992

2 EQX2 -706.683

2 EQX3 -706.683

2 WIND X -61.585



Table 4.34 Story Shear for East-West Direction

STORY LOAD CASE VX

(Kips)

MAX

(Kips)

STORY SHEAR

(Kips)

5 EQY1 -282.326

-282.326 -282.326 5 EQY2 -282.326

5 EQY3 -282.326

5 WIND Y -13.846

4 EQY1 -454.186

-454.186 -171.86 4 EQY2 -454.186

4 EQY3 -454.186

4 WIND Y -40.829

3 EQY1 -602.69

-602.69 -148.504 3 EQY2 -602.69

3 EQY3 -602.69

3 WIND Y -66.592

2 EQY1 -706.682

-706.682 103.992 2 EQY2 -706.682

2 EQY3 -706.682

2 WIND Y -90.811

4.3.2 ANALYSIS

Design for ―Actual Worst Case‖ Story Shear from Lateral Analysis



However, we will check this value against Fp as calculated from IBC 2006 (ASCE 7-05, EQ.

12.10)

∑

∑

Actual Calculated Fp Value (Design Story Shear) … (4.34)

Fp=0.2IESDSwp Minimum Calculated Fp Value … (4.35)

Fp=0.4IESDSwp Maximum Calculated Fp Value … (4.36)

IE=1.00 SDS=0.244

Table 4.35 Comparison between Lateral Analysis Story Shear and IBC Story Shear for N-S

Direction

Story

Shear

(Kips)

Story

Shear

(Kips)

Cumulative

Weight

(Kips)

Wt At

Each

Level

(Kips)

Fp

(Min)

(Kips)

Fp

(Max)

(Kips)

Design

Story

Shear

(Kips)

5 282.326 282.326 3030.97 3060.97 147.911 295.822 282.326

4 454.186 171.86 5848.32 2787.35 136.024 272.048 216.47

3 602.69 148.504 8635.67 2787.35 136.024 272.048 194.4

2 706.682 103.992 11423.03 2787.35 136.024 272.048 172.44

Table 4.36 Comparison between Lateral Analysis Story Shear and IBC Story Shear for E-W

Direction

Story

Shear

(Kips)

Story

Shear

(Kips)

Cumulative

Weight

(Kips)

Wt At

Each

Level

(Kips)

Fp

(Min)

(Kips)

Fp

(Max)

(Kips)

Design

Story

Shear

(Kips)

5 282.326 282.326 3030.97 3060.97 147.911 295.822 282.326

4 454.186 171.86 5848.32 2787.35 136.024 272.048 216.47

3 602.69 148.504 8635.67 2787.35 136.024 272.048 194.4

2 706.682 103.992 11423.03 2787.35 136.024 272.048 172.44



4.3.2.1 DIAPHRAGM ANALYSIS IN THE N-S DIRECTION

Entire Floor is assumed as one Single Diaphragm for the analysis in North-South Direction.

Fig. 4.16 Plan of Diaphragm under consideration in N-S direction

Critical Case Shear is at Level 5

Worst case shear loads occur at Level 5 =282.326 kips

Total load at worst case story Eu (kips/ft.) =282.326 kips/118.00‘

=2.393 kips/ft.

Seismic Force "E" is resisted by the Lite walls along Grid "B"

N SEISMIC

FORCE (E)



Fig. 4.17 Bending Moment and Shear Force Diagrams for Diaphragm in N-S direction

Worst Case Mu = (2.393 klf x 59 ^ 2) /2 =4165.02 kip-ft.

d = (177.58' - 7') =170.58'

Design Tu =4165.02 kips / 170.58 ft. =24.42 kips

Tu to be resisted by DT to ITB connection

4.3.2.2 DIAPHRAGM ANALYSIS IN THE E-W DIRECTION

Entire Floor is divided into (4) Separate Diaphragms -

2 Flat Diaphragms-Diaphragm #1 b/w Grids 'A-C'/'1-2'

Diaphragm #2 b/w Grids 'A-C'/'4-5'

2 Ramp Diaphragms-Diaphragm #3 b/w Grids 'A-B'/'2-4'

Diaphragm #4 b/w Grids 'B-C'/'2-4'

1.82 klf

C

59.0'

A

59.0'

B

107.4 kips

3167.7 kips-ft

118.0'

107.4 kips

Vu

Mu

2.393 kips/ft.

141.19 kips

141.19 kips

4165.02 kips/ft.



4.3.2.2.1 DIAPHRAGM ANALYSIS (#1 & #2)

Fig. 4.18 Plan of Diaphragm (#1 & #2)


Shear load is at Level 5 =282.326 kips

Total load at worst case story Eu (kips/ft.) =282.326 K/174.0‘=1.623 k/ft.

Seismic Force "E" is resisted by the Shear Walls along Grids "2" & "4".

N

SEISMIC

FORCE (E)



`


direction

Worst Case Mu = (1.23 klf x 42 ^ 2) /2 =1431.49 kip-ft.

D = (118' - 6') =112'

Design Tu =1431.49 kips / 112 ft. =12.78 kips

Tu to be resisted by "Chord Connections" within the Flanges of the DT's on Exterior

perimeter along Grids "A" & "C" and between Grids "1-2" & "4-5" at all Levels

1.623

42‘

68.17 Kips

1431.49 kips-ft

Kips



4.3.2.2.2 DIAPHRAGM ANALYSIS (#3 & #4)

Fig. 4.20 Plan of Diaphragm (#3 & #4)


Shear load is at Level 5 =282.326 kips

Total load at worst case story Eu (kips/ft.) =282.326 K/(174.0‘ * 2)=0.811 k/ft.

Seismic Force "E" is resisted by the Shear Walls along Grids "2" & "4".

N

SEISMIC

FORCE (E)




direction

Worst Case Mu = (0.811 klf x 90 ^ 2) / 8 =821.14 kip-ft.

d = (59' - 6') =53'

Design Tu =821.14 kips / 53 ft. =15.49 kips

Tu to be resisted by "Chord Connections" within the Flanges of the DT's on Exterior

perimeter along Grids "A", "B" & "C" and between Grids "2"-"4" at all Levels.

***

0.811 kips/ft.

90.00’

36.5 kips

36.5 kips

821.14 kips-ft.



CHAPTER 5

DESIGN OF CONNECTIONS

The design of connections is one of the most important considerations in the structural design

of a precast concrete structure. There are many successful solutions to each connection

condition. The purpose of a connection is to transfer load, restrain movement, and/or provide

stability. Within any one connection, there may be several load transfers; each one must be

designed for adequate strength and ductility and be appropriately detailed. The detailing

should take into account allowable tolerances, provide for a good fit between the selected

materials.

5.1 DESIGN OF FOUNDATION CONNECTIONS

Foundation connections are used in the part of the building where connections between pre-

cast products and CIP are required to be established. It helps in maintaining structural

integrity and hence improves the redundancy and ductility of structures, thereby reducing the

risk of failure or collapse of parts or all of a building due to damage occurring to a relatively

small area of a building.

5.1.1 DESIGN OF COLUMN FOUNDATION CONNECTIONS FOR COLUMN24'' x

34''

CONNECTION LOADS

TENSION LOADS

Since the Column is pocketed for Spandrels, Effective Gross Area Ag is considered only as

24'' x 21''

Tu,reqd =200 Ag =200 (24'' x 21'') =100.8 K … (5.1)

BEARING-AXIAL LOADS

Service DL to Column =760.1 K

Service LL to Column =185.7 K Pu = 1228.9 K

Service SL to Column =39.3 K



Fig. 5.1 Plan and Section of Column-Foundation Connection

Factored Load to Column =1.2 x 760.086 K + 1.6 x 185.698 K + 0.5 x 39.344 K

=1228.9 K



CONNECTION CAPACITIES

CAPACITY OF THREADED RODS

For 1 ½‘ Φ A36 Threaded Rod

Tn/bolt =Φ x A x Fu … (5.2)

=0.75 x 1.767 x 58 ksi

=76.9 K

Tn/col =4 x 76.9

=307.6 K > 100.8 K Hence, Design is OKAY

Table 5.1 Strength of bolts and Threaded fasteners

BEARING CAPACITY OF COLUMNS

Design Axial Strength =Ø(0.85) (f'c) (Ag - Ast) + fyAst …(5.3)

Considering Ast as As,min = 0.01 Ag

For 24" x 34" Column, Ag = 504.0 in2

ØPnb =(0.8) (0.85) (5) (504 - 5.04) + (60) (5.04)

=1998.9 K >1228.9 K Hence, Design is OK

Bolt Nominal A36, Fu = 58 ksi A36, Fu = 60 ksi

Diameter Area Tension Shear Tension Shear

in. A,in2 Design Service Design Service Design Service Design Service

1/2 0.196 6.4 3.8 3.4 1.9 6.6 3.9 3.5 2.0

5/8 0.307 10.0 5.9 5.3 3.0 10.4 6.1 5.5 3.1

3/4 0.442 14.4 8.5 7.7 4.4 14.9 8.8 8.0 4.4

7/8 0.601 19.6 11.5 10.5 5.9 20.3 12.0 10.8 6.0

1 0.785 25.6 15.0 13.7 7.7 26.5 15.7 14.1 7.9

1 1/4 1.227 40.0 23.5 21.3 12.1 41.4 24.5 22.1 12.3

1 1/2 1.767 57.6 33.8 30.7 17.4 59.6 35.3 31.8 17.7

2 3.142 102.4 60.1 54.7 31.0 106.0 62.8 56.6 31.4



5.1.2 DESIGN OF SHEAR WALL FOUNDATION CONNECTION

5.1.2.1 DESIGN OF SHEAR WALL FOUNDATION CONNECTIONS ALONG GRID

‘2’

CONNECTION LOADS

TENSION LOADS

Uplift at Ends of Shearwall, Tu =206.9 K (Refer section 4.2.3.1.2)

Use (6) #11's Bars ends, for Uplift

Tu/No. of Bars =206.9/6 K

=37.4 K

SHEAR LOADS

Shear: SW1 has Uplift/Tension, therefore the dead load on the compression side is permanent

and can be used to reduce the amount of shear friction reinforcement (per AC1 318-05

11.7.7)

Base Shear, Vu =417.2 K (Refer section 4.2.3.1.2)

ØVn (from DL on Comp. Side) = (0.9 - 0.2SDS)(0.5*Pdl)(m) … (5.4)

=199.6 K

Where, m =0.6

SDS =0.244

Pdl =736.8

ØVn (from #11's in shear friction) =(6) x 42.12 K

=252.7 K

Vu,rem./No. of Bars =229/6 K

=38.2 K

*Note: Vu,rem. = Vu - ØVn(from DL on Comp. Side)



Fig. 5.2 Section of Shear Wall-Foundation Connection



CONNECTION CAPCITIES

SHEAR CAPACITY

Using Shear Friction per PCI Design Handbook, 7th Edition m = 0.6

ØVn (Per #11 Bar) =(0.75) (60 ksi) (1.56 in2) (0.6)

=42.1 K> 38.2 K Hence, Design is OKAY

TENSION CAPACITY

ØTn (Per #11 Bar) =(0.9) (60 ksi) (1.56 in2)

=84.2 K> 37.4 K Hence, Design is OKAY

7.1.2.2 DESIGN OF SHEAR WALL FOUNDATION CONNECTIONS ALONG GRID

‘4’

CONNECTION LOADS

TENSION LOADS

Uplift at Ends of Shear wall, Tu =254.0 K (Refer section 4.2.3.2.2)

Use (6) #11's Bars ends, for Uplift

Tu/No. of bars =254.0/6 K

=42.3 K

SHEAR LOADS

Shear: SW2 has Uplift/Tension, therefore the dead load on the compression side is permanent

and can be used to reduce the amount of shear friction reinforcement (per AC1 318-05

11.7.7)

Base Shear, Vu =309.1 K (Refer section 4.2.3.2.2)

ØVn (from DL on Comp. Side) = (0.9 - 0.2SDS)(0.5*Pdl)(m) … (5.5)

=199.6 K

Where, m =0.6



SDS =0.244

Pdl =736.8

ØVn (from #11's in shear friction) =(6) x 42.12 K

=252.7 K

Vu,rem./No. of Bars =120.9/6 K

=20.2 K

*Note: Vu,rem. = Vu - ØVn (from DL on Comp. Side) … (5.6)

CONNECTION CAPACITIES

SHEAR CAPACITY

Using Shear Friction per PCI Design Handbook, 7th Edition m = 0.6

ØVn (Per #11 Bar) = (0.75) (60 ksi) (1.56 in2) (0.6)

=42.1 K>20.2 K Hence, Design is OKAY

TENSION CAPACITY

ØTn (Per #11 Bar) = (0.9) (60 ksi) (1.56 in2)

=84.2 K>42.3 K Hence, Design is OKAY

Table 5.2 Equivalent Area of Corresponding Steel Bars

Diameter(in) Area(in2)

5 0.31

6 0.44

7 0.60

8 0.79

9 1.00

10 1.27

11 1.56

14 2.25



5.2 DESIGN OF DOUBLE-TEE-SHEAR WALL CONNECTIONS

CONNECTION LOADS:

Table 5.3.Shear Loads in kips for each Shear walls at Corresponding Floor Levels for Shear

Wall at grid ‗2‘.

STORY CUM SHEAR

(Kips)

STORY SHEAR

Vu(Kips)

NO. OF

CONNECTIONS

VU/(No. of

Connections)

4 250.448 104.865 12 8.739

3 324.054 73.606 12 6.133

2 416.123 92.069 12 7.672

Table 5.4.Shear Loads in kips for each Shear walls at Corresponding Floor Levels for Shear

Wall at grid ‗4‘.

STORY CUM SHEAR

(Kips)

STORY SHEAR

Vu (Kips)

NO. OF

CONNECTIONS

VU/(No. of

Connections)

4 195.235 64.557 12 5.380

3 252.924 57.689 12 4.807

2 308.047 55.123 12 4.593

CONNECTION CAPACITY

Embed Plate in Double-Tee (Unistress STD Plate No. P108S2)

Shear taken by (2) 1/2" diameter studs

ØVn =15.30 kips

Eccentricity taken out by the #4 bars

ØTn = (0.9)*(0.2)*(60)*(1)

=10.80 kips



Fig 5.3 Section of Double-Tee to Shear Wall Connection



Tu =Vu x e/d … (5.7)

ØVn =ØTn (d/e) … (5.8)

= (10.8 kips)(8")/4.75

= 18.19 kips

Fig 5.4 Embed Plate in Double-Tee

Embed Plate in Shearwall (Dayton Superior - P38 Slotted Corewall Insert II)

ØVn = 8.7 * 3 * .75

= 19.6 K

Strap Plate for Insert (JVI PSA Strap Anchor 2" wide x 8" long with e = 3")

ØVn = 11.3 K Controls Shear

Since Shear Capacity, 11.3 K > Connection Load, 8.739 K, Design is OKAY



Fig. 5.5 Embed Plate in Shear Wall.

Fig. 5.6 Strap Plate for Insert



CHAPTER 6

GRAVITY ANALYSIS OF PRE-CAST/PRE-STRESSED COMPONENTS

6.1 DESIGN OF DOUBLE-TEE SECTIONS USING PRESTO

6.1.1 DESIGN OF DOUBLE-TEE FLANGE CONNECTION FOR END CONDITION

DESIGN DATA INPUT:

Thickness of Precast Flange, tf =4.000in.

Depth to Flange Steel, d =2in.

Length of Cantilever, Lc =3.13ft.

Distance between Stems, S =6.3ft

Influence Angle, θ =60.0˚ (Per PCI 7th Edition, Chapter 5, Section

5.12.1. research suggests an influence angle of

60˚ results in an effective width consistent with

crack patterns from actual load tests.)

Concentrated Load - Loaded Area Length, x =4.50in.

Concentrated Load - Loaded Area Width, y =4.50in.

Distributed Live Load, wLL =0.04ksf

Distributed Snow Load, wSL =0.0336ksf

Concentrated Load, P =2.00kips (Since some of the concentrated load

is shared by adjacent DT through flange/chord

connection 70% of3K = 2K of concentrated load

is considered.)

Concrete Strength, f'c =6.0ksi

Mesh Steel Yield Strength, fy =60.0ksi

Weight of Precast Flange Concrete, wt =0.15kcf



Width of Design Section, b =1ft

Strength Reduction Factor, Φ =0.9

LOAD AT THE END OF DOUBLE-TEE (CORNER CONDITION)

Fig 6.1 Load Distributions at the cantilever portion of the Double-Tee

Self-weight of Precast Flange = (tf/12) * wt … (6.1)

= (4/12)*0.15

=WDL, TOTAL

=0.050 ksf

Effective Width of Cantilever, E = tanθ(Lc-(0.5x/12)) + (y/12) … (6.2)

=tan60(3.125-(2.25/12)) + (4.5/12)

=5.46ft.

LOAD CONDITION #1 -Self Weight + Concentrated Load, P

Mu,DL =1.2(WDL,TOTAL*Lc*Lc/2*12) … (6.3)

=1.2*(0.05*3.125*(3.125/2)*12)

=3.52k-in/ft

Mu,LL =1.6((P*Lc*12)/E)



=1.6*((2*3.125*12)/5.46)

=21.98 k-in/ft

MU1 =Mu,DL+ Mu,LL =3.52 + 21.98

=25.50 k-in/ft.

LOAD CONDITION #2 -Self Weight + Distributed Live Load

WDL,TOTAL =0.05 ksf

WLL,TOTAL =WLL + WSL

=0.04 + 0.0336

=0.074 ksf

WU =1.2WDL,TOTAL+ 1.6WLL,TOTAL … (6.4)

=1.2*(0.05) + 1.6*(0.0736)

=0.180 ksf

MU2 = (Wu*Lc*Lc/2*12) … (6.5)

=0.18*3.125*(3.125/2)*12

=10.55 k-in/ft.

LOAD BETWEEN STEMS

Fig. 6.2 Load Distributions at the stem portion of the Double-Tee




Mu,DL =1.2(WDL,TOTAL*S2/8*12) … (6.6)

=1.2*(0.05*(6.25^2/8)*12)

=3.52 k-in/ft

Mu,LL =1.6((P*S*12)/4E) … (6.7)

=1.6*((2*6.25*12)/(4*5.46))

=10.99 k-in/ft

MU3 = Mu,DL + Mu,LL =3.52 + 10.99

=14.51 k-in/ft


WDL,TOTAL =0.050 ksf

WLL,TOTAL =0.074 ksf

WU =0.180 ksf

MU4 = (Wu*S2/8*12) … (6.8)

=0.18*(6.25^2/8) *12

=10.55 k-in/ft

Determine Area of Steel Required for 1' Width of Flange

MU1 =25.50 k-in/ft.

MU2 =10.55 k-in/ft. Max Mu = 25.50 k-in/ft.

MU3 =14.51 k-in/ft.

MU4 =10.55 k-in/ft.



ΦMn =ΦAsfy (d - (Asfy/1.7bf'c)) … (6.9)

= (ΦAs2fy2/1.7bf'c) - ΦAsfyd + Mu = 0

Using the Quadratic Equation, As = √

… (6.10)

= √

=3.83in2/ft or 0.25in2/ft

Therefore required As is 0.25 in2/ft

Thus, Provide WWR 12x4 - d4.0 x d4.5 (equivalent area=0.135 in2/ft) mesh throughout

the length of the tee and provide (1) #4 (equivalent area=0.2 in2/ft) at the ends of the

double tees.

Provided As =0.34 in2/ft.>0.25 in2/ft. OK

ΦMn = (0.9*0.34*60)(2-(0.34*60)/(1.7*6*12))

=33.66 k-in/ft. > Max Mu =25.50 k-in/ft OK

6.1.2 DESIGN OF DOOUBLE-TEE FLANGE CONNECTION FOR INTERIOR

CONDITION

DESIGN DATA INPUT:

Thickness of Precast Flange, tf =4.000in.

Depth to Flange Steel, d =2in.

Length of Cantilever, Lc =3.13ft.

Distance between Stems, S =6.3ft

Influence Angle, θ =60.0˚ (Per PCI 7th Edition, Chapter 5, Section

5.12.1. research suggests an influence angle of

60˚ results in an effective width consistent with

crack patterns from actual load tests.)



Concentrated Load - Loaded Area Length, x =4.50in.

Concentrated Load - Loaded Area Width, y =4.50in.

Distributed Live Load, wLL =0.04ksf

Distributed Snow Load, wSL =0.0336ksf

Concentrated Load, P =3.00kips

Concrete Strength, f'c =6.0ksi

Mesh Steel Yield Strength, fy =60.0ksi

Weight of Precast Flange Concrete, wt =0.15kcf

Width of Design Section, b =1ft

Strength Reduction Factor, Φ =0.9

LOAD AT THE END OF DOUBLE-TEE (CORNER CONDITION)

Fig.6.3 Load Distributions at the cantilever portion of the Double-Tee.

Self-weight of Precast Flange = (tf/12) * wt … (6.11)

= (4/12)*0.15

=WDL, TOTAL

=0.050 ksf



Effective Width of Cantilever, E = 2tanθ(Lc-(0.5x/12)) + (y/12) … (6.12)

= 2tan60(3.125-(2.25/12)) + (4.5/12)

= 10.55ft.


Mu,DL =1.2(WDL,TOTAL*Lc*Lc/2*12) … (6.13)

=1.2*(0.05*3.125*(3.125/2)*12)

=3.52k-in/ft

Mu,LL =1.6((P*Lc*12)/E)

=1.6*(((3/2*3.125*12)/10.55)

=21.98 k-in/ft

MU1 =Mu,DL+ Mu,LL =3.52 + 8.53

=12.05 k-in/ft.


WDL,TOTAL =0.05 ksf

WLL,TOTAL =WLL + WSL

=0.04 + 0.0336

=0.074 ksf

WU =1.2WDL,TOTAL+ 1.6WLL,TOTAL

=1.2*(0.05) + 1.6*(0.0736)

=0.180 ksf

MU2 = (Wu*Lc*Lc/2*12)

=0.18*3.125*(3.125/2)*12

=10.55 k-in/ft.



LOAD BETWEEN STEMS

Fig. 6.4 Load Distributions at the stem portion of the Double-Tee


Mu,DL =1.2(WDL,TOTAL*S2/8*12) … (6.14)

=1.2*(0.05*(6.25^2/8)*12)

=3.52 k-in/ft

Mu,LL =1.6((P*S*12)/4E) … (6.15)

=1.6*((3*6.25*12)/(4*10.55))

=8.53 k-in/ft

MU3 = Mu,DL + Mu,LL =3.52 + 8.53

=12.05 k-in/ft


WDL,TOTAL =0.050 ksf

WLL,TOTAL =0.074 ksf

WU =0.180 ksf

MU4 = (Wu*S2/8*12) … (6.16)



=0.18*(6.25^2/8) *12

=10.55 k-in/ft.

Determine Area of Steel Required for 1' Width of Flange

MU1 =12.05 k-in/ft.

MU2 =10.55 k-in/ft. Max Mu = 12.05 k-in/ft.

MU3 =12.05 k-in/ft.

MU4 =10.55 k-in/ft.

ΦMn = ΦAsfy (d - (Asfy/1.7bf'c)) … (6.17)

= (ΦAs2fy2/1.7bf'c) - ΦAsfyd + Mu = 0

Using the Quadratic Equation, As = √

… (6.18)

= √

=3.97in2/ft. or 0.11in2/ft.

Therefore required As is 0.11 in2/ft.

Thus, Provide WWR 12x4 - D4.0 x D4.5 (equivalent area=0.135 in2/ft) mesh throughout

the length of the tee

Provided As =0.14 in2/ft>0.11 in2/ft OK

ΦMn = (0.9*0.14*60)(2-(0.14*60)/(1.7*6*12))

=14.60 k-in/ft > Max Mu =12.05 k-in/ft OK



6.2 DESIGN OF INVERTED-TEE BEAM SECTIONS USING PRESTO

6.2.1 DESIGN OF INVERTED-TEE BEAMS FOR THE ROOF LEVEL

ITB is located Along Grid 'B' and b/w Grids '1' & '2' at Roof Level with a Span of 39'-10‘.

Fig. 6.5 ITB Load Layout

Fig. 6.6 C/S at A-A

Load Combination: 1.2DL + 1.0LL + 1.6SL Controls Design Bending



Details of Inverted-Tee Beam

Span = 39.83 ft

Web width = 32.00 in

LL on web = 40.00 psf

SL on web = 33.6 psf

LL on web in klf = 40/1000 x 32/12

= 0.11 klf

SL on web in klf = 33.6/1000 x 32/12

= 0.09 klf

Table 6.1 Shear forces for various Pier Labels

DL in Kips LL in Kips SL in Kips Vu Vudl

P1 15.2 7.0 5.9 34.7 1.82

P2 17.6 8.8 7.4 41.8 21.1

P3 9.2 3.9 3.3 20.2 11.0

P4 13.9 5.9 4.9 30.4 16.7

P5 15.2 7.0 5.9 34.7 18.2

LEDGE REINFORCEMENT DESIGN

Height of Beam, h = 35.25 in.

Height of Ledge, hl = 12.0 in.

Depth to Tensile Bar As, d = 10.22 in.

Depth to Longitudinal Bar Al, dl = 9.25 in.

Width of Web, b = 32.0 in.

Width of Web + Width of One Ledge,bl = 40.0 in.



Distance from Ext. Face to CL of Ash Reinforcing, ds = 30.22 in.

Centerline of Ash Reinforcing to Load Vu, a = 7.78 in.

Centerline of Web to Load Vu, e = 22.0 in.

Distance from Center of Load to End of Beam, de = 5.50 in.

Spacing Between First 2 Loads, s = 90.0 in.

Width of Bearing Area, bt = 6.88 in.

Concrete Strength, f'c = 6.0 ksi

Steel Yield Strength, fy = 60 ksi

Strength Reduction Factor = 0.75

Vertical Load, Vu = 20.0 kips

Roof Level Beam along Grid Line '8', near "G.8" Vudl = 10.9 kips

Horizontal Load, Nu = 0.2 x Vudl, Nu = 2.18 kips

Fig. 6.7 Ledge of Inverted-Tee Beam



TRANSVERSE (CANTILEVER) BENDING OF THE LEDGE

AS,REQ'D = [1/Φfy] * [Vu(a/d) + Nu(hl/d)] … (6.19)

= 1/(0.75*60)*[20(7.78/10.22)+2.184(12/10.22)]

= 0.40 in2

Distribute Steel over a distance of

de + 6hl = 78''

de + s/2 = 50.5''

de + (bt + hl)/2 =14.9'' Controls … (6.20)

Therefore, AS,REQ'D =0.4/(14.9375/12)

=0.33 in²/ft.

PROVIDE #4 STIRRUPS at 6 in. O.C.

As(PROVD.) = (0.20/0.50)

= 0.40 in2/ft. >0.33 in2/ft.

HENCE O.K

LONGITUDINAL BENDING OF THE LEDGE

Al,REQ'D = 200 (bl - b) dl / fy … (6.21)

=[200*(40-32)(9.25/60)]/1000

= 0.25 in² for fy = 60 ksi

Al,REQ'D = 200 (bl - b) dl / fy … (6.22)

= [200*(40-32)(9.25/270)]/1000

= 0.06 in² for fy = 270 ksi

Therefore Provide (1) #5 Bar at Top & Bottom of Ledge

AL(PROVD.) = (0.31) (1) = 0.31 in2 > 0.25 in2 HENCE OK



TORSION AND SHEAR REINFORCEMENT

TRANSVERSE REINFORCING:

1) (Av + 2At) REQ‘D from Presto run. = 0.28 in.2 / ft. … (6.23)

2) (Ash) REQ‘D (From Hanger Steel Req.) = 0.66in.2 / ft.

(0.33 in.2 / ft. x 2)

(Av + 2At)PROV'D = (0.2 x 2 x 12/6)

= 0.80 in2/ft. > 0.66 in2/ft.

HENCE O.K

Therefore Provide #4 Stirrups at 6" O.C.

LONGITUDINAL REINFORCING:

AL,REQ'Dfrom Presto = 6.83 in.2

Therefore Provide ( 6 ) #7 Hair Pins.

AL,PROV'D = (0.60) ( 6 ) ( 2 )

= 7.20 in.2 > 6.83 in.2 HENCE O.K.

Therefore Provide (6) #7 X 6'-0" Lg. U-Bars



6.3 DESIGN OF SPANDREL SECTIONS USING PRESTO

Span of Spandrel – 44.92‘

Fig 6.8 Loads acting on the Spandrel

Fig. 6.9 C/S of the given spandrel



Table no. 6.2 Reaction from DT stem on LB spandrel in Kips

DL LL VU VUdl

P1 17.6 13 41.9 21.1

Table no. 6.3 Loads in Klf

DL

P2 0.214

TORSION AND SHEAR REINFORCEMENT

TRANSVERSE REINFORCING: at ENDS (0' to 2') at ENDS (2' TO 14') at INTERIOR

(Av + 2At)REQ'D from Presto = 0.15 in.2 / ft. 0.15in.2/ ft. 0.04 in.2/ ft.

AT END (OUT TO 2'-0")

-With #4 Closed Ties At 6" O.C.

(Av + 2At)PROV'D = (0.2 x 12"/6" x 2) … (6.24)

= 0.80in2/ft. > 0.15 in2/ft.

HENCE OKAY

Provide #4 Closed Ties At 6" O.C. For 2'-0" At End

AT END (FROM 2'-0" TO 14'-0")

-With #4 Closed Ties At 12" O.C.

(Av + 2At)PROV'D = (0.2 x 12"/12" x 2) … (6.25)

= 0.40in2/'ft. > 0.15 in2/ft.

HENCE OKAY

Provide #4 Closed Ties at 12" O.C. From 2'-0" To 14'-0" At Each End



AT MID-PORTION (BALANCE)

-With One Layer Of "Fm7" Mesh At Ext. Face And One Layer Of "Fm9" Mesh at Interior

Face (Both Have D7 Wires at 16" O.C. Max).

(Av + 2At)PROV'D = (0.07 x 12/16 x 2) = 0.11 in2/ft. > 0.04 in2/ft. … (6.26)

HENCE OKAY

Provide (1) Layer Of "Fm7" Mesh at Exterior Face And Provide (1) Layer Of "Fm9"

Mesh at Interior Face

LONGITUDINAL REINFORCING:

AT END:

AL,REQ'D from Presto run = 4.05 in2

Provide ( 5 ) #6 Hair Pins

AL,PROV'D = (0.44 ) ( 5 ) ( 2 )

=4.40 in.2> 4.05 in.2 HENCE OKAY.

AT MID PORTION:

AL ,REQ'D from Presto run =4.37 in2

Provide (10) #6 Continuous Bars

AL,PROV'D = ( 0.44 ) ( 10 )

= 4.40 in.2> 4.37 in.2

HENCE OKAY

Provide (5) #6 X 5'-0" Long. U-Bars with (10) #6 X Continuous Bars



6.4 DESIGN OF COLUMN SECTIONS USING VERTEX

Fig. 6.10 Loading Diagram Fig. 6.11SectionA-A



Fig. 6.12 Cross Section of Column

Table 6.4 Loads and Moment on P1 and P2

P1 P2

DL(Kips) 76.5 76.5

Mx(Kips-in) 1539.6 1539.6

Mz(Kips-in) 688.5 688.5

LL(Kips) 26.4 26.4

Mx(Kips-in) 531.3 531.3

Mz(Kips-in) 237.6 237.6

SL(Kips) 22.2 -

Mx(Kips-in) 446.8 -

Mz(Kips-in) 199.8 -

Vu(Kips) 153.7 134.0

Vudl(Kips-in) 91.8 91.8

24"

34

"+ Mx

X

ex=

9"

ex=

-9"

z

+ Mz

21

12"

12

12"

PK

T.

P1/P2P1/P2

ex=

9"

ex=

-9"

ez=

+2

01

8"

DESIGN

SECTION

TOP FACE

CL

CL

LEFT FACE



According to IBC-2006 - Section 1605.2.1

Load Combinations:

1) 1.2 DL + 1.6 LL + 0.5 SL

2) 1.2 DL + 1.6 LL (Max. LL on one side) + 0.5 SL

3) 1.2 DL + 1.0 LL + 1.6 SL

4) 1.2 DL + 1.0 LL (Max. LL on one side) + 1.6 SL

MIN. / MAX COLUMN REINFORCEMENT (PER ACI SECTION 10.9.1)

Column Width = 24 in.

Column Depth = 21.5 in.

Gross Column Area (Ag) = 516.0 in.2

As min = 0.01 Ag

= 5.16 in2

As max = 0.08 Ag

= 41.28 in2

PROVIDE 4 #11 BARS

As,PROV'D = 4*1.56in2

=6.24 in2

As min < As PROV'D < As max HENCE O.K.

DETERMINE COLUMN TIE SPACING (PER ACI SECTION 7.10.5)

USING #11 LONGITUDINAL BARS

SPACING NOT TO EXCEED:

16 LONGITUDINAL BAR DIAMETERS =16 * 1.41in. =22.6in



48 TIE BAR DIAMETERS = 48 *0.5 in. =24.0 in

LEAST DIMENSION OF THE COLUMN = 21.5 in. =21.5 in

SPACE# 4 TIES at 21'' MAX

6.5 DESIGN OF SHEAR WALL SECTIONS USING VERTEX

SW Design Approach Summary

This project was determined to be seismic design category 'B' and has a lateral force resisting

system that is defined as a "Bearing Wall System" comprised of "Intermediate Precast Shear

walls".

The Codes and Standards followed are IBC 2006[15] (New York State Building Code 2010),

ASCE 7-05[13]Per ACI 318-05[14], Section 21.1 as added by IBC 2006[15] Section

1908.1.3, the vertical elements of the Shear walls are permitted to be designed as "wall piers"

as long as they meet certain dimensional criteria. On this project all vertical elements shall be

designed as wall piers. Per ACI 318-05[14] Section 21.2.1.2, as modified by IBC 2006[15]

section 1908.1.4, for Seismic Design Category 'B' Structures, the vertical "wall pier" elements

and the solid portions above and below the openings may be designed and reinforced in

accordance with ACI 318-05[14] chapter 1 thru 18 and 22. Since the Shear walls are

considered as "Intermediate Precast Shear walls" and Structure falls within the Seismic

Design Category 'B' region, no special ductile detailing is required to be considered for the

design. The Shear walls are hence reinforced "nominally" to resist both Lateral and Gravity

loads. Below listed is the step by step approach.

Lateral Design:

Shear walls "SW1" & "SW2" are combined into a Single group since all of them support

same loadings. Critical SW among each group is designed for its Lateral Loadings by

designing their Vertical Column Strips as Wall piers. These Wall piers are adequately

designed to resist both Shear and Flexure due to Lateral Forces. Horizontal portions above

openings are designed to resist cumulative shear at given level and reinforced accordingly.

Gravity Design:

The most critical full-height "Pilaster section" is analysed for gravity loads.



Fig. 6.13 Shear Wall along Grid B2 and B4



SHEARWALL DESIGN TO RESIST LATERAL LOADS

Shear wall Elevation for SW's at grid 'B/2' (Critical Case)

Fig 6.14 12‖ Shear Wall

Determine if Vertical Sections Can be Classified as Wall Piers

-Per IBC 2006, Section 1908.1:

Horizontal length-to-thickness ratio is between 2.5 and 6.

Clear height is at least two times the horizontal length.

at End Vertical Segments

Horizontal Length-to-Thickness Ratio = 5.00'/1.00‘ = 5.0 Consider as a Wall Pier

Clear Height-to-Length Ratio = 5.00'/5.00‘ =1.0 Conservatively consider as a Wall Pier

at Middle Vertical Segment

Horizontal Length-to-Thickness Ratio = 10.00'/1.00‘ = 10.0 Consider as a Wall

Clear Height-to-Length Ratio = 5.00'/10.00‘ = 0.5 Consider as a Wall



Distribution of Shear Force to each Vertical Wall Pier Element

Worst-Case Total Shear, Vu =417.2 Kips (Refer section 4.2.3.1.2)

Total width of all segments = 2 x 5.00' + 10‘

=20‘

Shear Force Applied to Each Vertical Segment :

at End Vertical Segments

Vu / (Segment length) = 422.4 K (5.00/20.00)

= 104.3 Kips

Design for Moment:

Worst Case Shear,Vu =104.30 kip

Worst Case Moment, Mu =Vu * (h/2)

=104.3 * (5.00/2)

=260.75 ft-kips

Felxural Design Strength, ΦMn =322.55 ft-kips (From Presto Run)

Since 322.55 ft-kips > 260.75 ft-kips HENCE O.K.

Provide #4 Bars at 12" O.C in both Hoizontal & Vertical Direction with #5 bar at Opening

Design for Shear: ACI 318 - 08 (Eq. 11-1 & 11-2)

Width of compression face of component, b = 12in.

Distance from extreme compression fiber to centroid of tension reinforcement, d=58in.

Specified compressive strength of concrete, f‘c=6ksi

Specified yield strength of reinforcement, fy =60ksi

Center-to-center spacing of reinforcement, wires, or anchors, s=12in

Figure 6.15 Line Diagram of

Column, h=5‘.

*Note: Consider top & bottom

end of vertical leg to be fixed at

beam section



Strength-reduction factor, Φ = 0.75


Factored Shear Strength, φVc =Φ *2*SQRT(f'c)*b*d … (6.27)

= 0.75 * 2 * SQRT(6000) * 12.00 * 58.00

=80.9 kips

Φ Vc / 2 =40.4 kips

Therefore, Vu > φVc

Hence, provide As,reqd to satisfy Vn = Vc + Vs, Av,min or (50*b*s)/fy

φVs,req'd = Vu - φVc … (6.28)

=105.6 - 80.87

=24.73 kips

Av,min =φ * SQRT(f'c) * ((b*s) / fy)

=0.75*SQRT(6000)*((12.00*12.0)/60000)

=0.14 in2/ft

or =(50 * b * s) / fy

=(50 *12.00 * 12.0) / 60000

=0.12 in2/ft

or =(Vs,req'd * s) / (φ * fy * d)

=(24.73 * 12.0) / (0.75 * 60 * 58.00)

Therefore Av,min =0.11 in2/ft.

Provide #4 Bars @ 12" O.C. in both Hoizontal & Vertical Direction which is =0.8 in2>.14 in2



6.5 DESIGN OF LITE WALL SECTIONS USING VERTEX

This design type covers all horizontal litewalls along Grid "B"

Lite Wall Design Approach Summary

This project was determined to be seismic design category 'B' and has a lateral force resisting

system that is defined as a "Bearing Wall System" comprised of "Intermediate Precast

Shearwalls". The Codes and Standards followed are IBC 2006[4] (New York State Building

Code 2010), ASCE 7-05[13] Per ACI 318-05[14], Section 21.1 as added by IBC 2006[15]

Section 1908.1.3, the vertical elements of the Litewalls are permitted to be designed as "wall

piers" as long as they meet certain dimensional criteria. On this project all vertical elements

shall be designed as wall piers. Per ACI 318-05[14] Section 21.2.1.2, as modified by IBC

2006[15] section 1908.1.4, for Seismic Design Category 'B' Structures, the vertical "wall

pier" elements and the solid portions above and below the openings may be designed and

reinforced in accordance with ACI 318-05[14] chapter 1 thru 18 and 22. Since the Litewalls

are considered as "Intermediate Precast Shearwalls" and Structure falls within the Seismic

Design Category 'B' region, no special ductile detailing is required to be considered for the

design. The Litewalls are hence reinforced "nominally" to resist both Lateral and Gravity

loads. Below listed is the step by step approach.

Lateral Design:

Litewalls "LiteWalls1" & "LiteWalls2" are combined into a Single group since Both of them

support same loadings. Critical LW among each group is designed for its Lateral Loadings by

designing their Vertical Column Strips as Wall piers. These Wall piers are adequately

designed to resist both Shear and Flexure due to Lateral Forces.

Gravity Design:

The most critical full-height "column strip" is analyzed for gravity loads with Out-of-Plane

moments incombination with the seismic orthogonal (In-plane) moments at the top and

bottom of each vertical wall pier elements.

The elevation of a litewall is shown in Fig. 6.16.



Fig. 6.16 LiteWall Elevation for LiteWall's along grids 'B' between grids '3' and '4'

Determine if Vertical Sections Can be Classified as Wall Piers

-Per IBC 2006, Section 1908.1:

Horizontal length-to-thickness ratio is between 2.5 and 6.

Clear height is at least two times the horizontal length.

at End Vertical Segments near Grid ‗3‘


Clear Height-to-Length Ratio = 6.00'/5.46‘ =1.1 Conservatively consider as a Wall Pier

at Interior Vertical Segment


Clear Height-to-Length Ratio = 6.00'/3.50‘ = 1.7 Conservatively consider as a Wall Pier



Clear Height-to-Length Ratio = 6.00'/4.50‘ = 1.3 Conservatively consider as a Wall Pier



Distribution of Shear Force to each Vertical Wall Pier Element

Worst-Case Total Shear, Vu =360.2 Kips (Refer section 4.2.2.2)

Total width of all segments = 4.5' + 4 x 3.5' + 5.46'

=23.96'

Shear Force Applied to Each Vertical Segment :



= 72.9 Kips

at Interior Vertical Segment


= 46.7 Kips


Vu / (Segment length) = 360.2 K (4.50/23.96) = 60 Kips

Wall Pier Design at End Vertical Segments near Grid ‘3’

Design for Moment:



=72.90 * (5.00/2)

=218.70 ft-kips

Flexural Design Strength, ΦMn =265.15 ft-kips (From Presto Run)


Provide (2) #5 Bars at each side of wall pier and (2) #5 bar at Center

Fig. 6.17 Line Diagram of

Column, h=6‘.

*Note: Consider top &

bottom end of vertical leg to

be fixed at beam section





Distance from extreme compression fiber to centroid of tension reinforcement, d=63.50in.







= 0.75 * 2 * SQRT(6000) * 12.00 * 63.50

=88.5 kips

Φ Vc / 2 =44.3 kips

Therefore, Vu < φVc

Hence, Provide Av,min or (50*b*s)/fy

Av,min =φ * sqrt(f'c) * ((b*s) / fy) … (6.30)

=0.75*SQRT(6000)*((12.00*12.0)/60000)

=0.14 in2/ft

or =(50 * b * s) / fy

=(50 *12.00 * 12.0) / 60000

=0.12 in2/ft

Provide (2) Layer(s) of WWR 4X4 - W4.0/W4.0 mesh which is .24 in2> .12in2



Wall Pier Design at Interior Segments

Design for Moment:



=46.70 * (5.00/2)

=140.10 ft-kips

Felxural Design Strength, ΦMn =166.79 ft-kips (From Presto Run)











Factored Shear Strength, φVc =Φ *2*SQRT(f'c)*b*d…(6.31)

= 0.75 * 2 * SQRT(6000) * 12.00 * 40

Fig 6.18 Line Diagram of

Column, h=6‘.

*Note: Consider top &

bottom end of vertical leg to

be fixed at beam section



=55.8 kips

Φ Vc / 2 =27.9 kips



Av,min =φ * SQRT(f'c) * ((b*s) / fy) … (6.32)

=0.75*SQRT(6000)*((12.00*12.0)/60000)

=0.14 in2/ft

or =(50 * b * s) / fy

=(50 *12.00 * 12.0) / 60000

=0.12 in2/ft

Provide (2) Layer(s) of WWR 4X4 - W4.0/W4.0 mesh which is 0.24 in2> 0.12in2

Wall Pier Design at Interior Segments

Design for Moment:



=60.10 * (5.00/2)

=180.30 ft-kips

Felxural Design Strength, ΦMn =217.02ft-kips (From Presto Run)



Fig. 6.19 Line Diagram of

Column, h=6‘.












= 0.75 * 2 * SQRT(6000) * 12.00 * 40

=72.50 kips

Φ Vc / 2 =36.30 kips



Av,min =φ * SQRT(f'c) * ((b*s) / fy) … (6.34)

=0.75*SQRT(6000)*((12.00*12.0)/60000)

=0.14 in2/ft

or =(50 * b * s) / fy

=(50 *12.00 * 12.0) / 60000

=0.12 in2/ft

Provide (2) Layer(s) of WWR 4X4 - W4.0/W4.0 mesh which is 0.24 in2> 0.12in2

***



CHAPTER 7

CONCLUSION

7.1 CONCLUSION

The parking structure was analysed for lateral loads using ETABS. Shear walls and

diaphragms are designed to take up acting lateral forces. Lateral Analysis includes the

following-

o Overturning Analysis of Shear Walls

o Diaphragm Analysis

Connections are designed to connect separate components of the parking structure to

develop integrity of the structure. The connections designed are as follows-

o Double-Tee Shear Wall Connection

o Foundation Column Connection

o Shear Wall Foundation Connection

Individual components of the parking structure are designed using PRESTO and

VERTEX so that the moments developed in the elements are lesser than the moment

strength of the elements. The individual elements designed are as follows-

o Double-Tee Section

o Spandrels

o Inverted-Tee Beams

o Columns

o Shear Walls

o Lite Walls

***



REFERENCES

[1] PCI Design Handbook-7TH EDITION published by PCI Industry Handbook Committee in U.S.A. in 2007.

[2] Michael Lepech, ―Sustainable Design and Manufacturing of Prefabricated Durable Infrastructure‖, CIFE proposal, Stanford, 2009.

[3] Kaar, P.H., L.B. Kriz, and E. Hognestad, ―Precast-Prestressed Concrete Bridges‖, 1. Pilot Tests of Continuous Girders. Journal of PCA Research and Development

Laboratories, 2(2), pp. 21–37, 1960.

[4] Mirmiran, A., S. Kulkarni, R. Miller, M. Hastak, B. Shahrooz, and R. Castrodale. ―Positive Moment Cracking in the Diaphragms of Simple-Span Prestressed Girders

Made Continuous.‖, American Concrete Institute, Detroit, pp.117–134, 2001.

[5] Mattock, A.H. and P.H. Kaar. ―Precast-prestressed Concrete Bridges III: Further Tests

of Continuous Girders‖. Journal of PCA Research and Development Laboratories,

2(3), pp. 51–78, 1960.

[6] ACI 318 ―Building Codes Requirement of Structural Concrete‖ published by American Institute Committee 318 in U.S.A. in 1977.

[7] ACI 318 ―Building Codes Requirement of Structural Concrete‖ published by

American Institute Committee 318 in U.S.A. in 2002.

[8] Ronald, H.D.‖ Design and Construction Considerations for Continuous Post-

tensioned Bulb Tee Girder Bridges‖. PCI Journal, Vol. 46, No. 3, pp. 44–66, 2001.

[9] Ng Ban Kiong, Zainal Abidin Akasah, ―An Overview Of Precast Concrete System

For Building Maintenance: Malaysian Perspective‖ Volume-2, Issue-6, 1684 – 1689,

2012.

[10] KSIIDC-IL&FS Project Development Company (KIPDC), ―Development Of Multi

Level Car Parking Facilities‖, 2009.

[11] Jack P. Moehle, Tony Ghodsi, John D. Hooper, David C. Fields, Rajnikanth Gedhada,

―Seismic Design of Cast-in-Place Concrete Special Structural Walls and Coupling

Beams.‖, NEHRP Seismic Design Technical Brief No. 6, 2006.

[12] Wan, G., R. B. Fleischman, and D. Zhang. "Effect of Spandrel Beam to Double Tee

Connection Characteristic on Flexure- Controlled Precast Diaphragms", Journal of

Structural Engineering, 2012.



[13] ASCE-07 ―Minimum Design Load For Building And Other Structure‖ published by American Society for Civil Engineers in U.S.A. in 2005.

[14] ACI 318 ―Building Codes Requirement Of Structural Concrete‖ published by American Institute Committee 318 in U.S.A. in 2008.

[15] IBC-2006 ―Design Standardization‖ published by International Code Councilin U.S.A. in 2006.

[16] Ghosh, S.K. and A. W. DomelJr..―Design of Concrete Buildings for Earthquake and

Wind Forces‖ .Skokie, IL: Portland Cement Association, 1992.

[17] Abdel-Karim, A. M., and Maher K. Tadros. ―Stretched-Out Precast Concrete I-Girder

Bridge Spans. Concrete International‖, V. 13, No. 9, September, 1991.

[18] World Commission on Environment and Development, ―Report on Our Common

Future,‖ Oxford University Press, New, York, NY, 1987.

[19] Jorge Gutierrez, ―Reglamento de Diseño Estructuralpara la República de Panamá‖

REP-2003 (―Structural Design Code for the Republic of Panama‖), 2003.

[20] J. Humar and M.A. Mahgoub, ―Determination of seismic design forces by equivalent

static load method‖, Department of Civil and Environmental Engineering, Carleton

University,1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada, 2006.

[21] Timothy P. McCormick, ―Shear Walls‖, Seismic Retrofit Training, 2000.

[22] N Krishna Raju, ―Pre-Stressed Concrete‖, Tata Mcgraw Hill Publishing Company, 4th

Edition, 2007.

[23] Gawade S.S. &Chawan D.S., ―Load-deflection analysis of flat & corrugated stainless

steel diaphragms by theoretical & finite element method‖, International Journal of

Engineering Research and Applications, Vol. 3, Issue 4, Jul-Aug 2013, pp.799—802.

[24] Jingyao Zhang, Makoto Ohsaki and Atsushi Uchida, ―Equivalent Static Loads For

Nonliner Seismic Design Of Spatial Structures‖, World Conference on Earthquake

Engineering, October 12-17, 2008, Beijing, China.

[25] David T. Finley, Ricky A. Cribbs, ―Equivalent Static vs. Response Spectrum A

Comparison of Two Methods‖, HLA Engineers, Inc., 7267 Envoy Ct., Dallas, TX,

USA 75247.

[26] Philip Line, William L. Coulbourne, ―ASCE 7-10 Wind Provisions and Effects on

Wood Design and Construction‖, 2008.



[27] Anil K Chopra, ―Dynamics of Structures‖, Pearson, Prentice Hall, 3rd Edition, 2007.

***



ANNEXURES

[A1] The source is PCI DESIGN HANDBOOK-7TH EDITION published by PCI

Industry Handbook Committee in U.S.A. in 2007 with ISBN 978-0-937040-87-4,

Design Aid 4.11.3SNOW LOADING.





TableDesign Aid 4.11.1Classification of Building and Other Structures for

Importance Factors Ia.





TableDesign Aid 4.11.5Basic Wind Speed, mph (m/s).





Table Design Aid 4.11.6 Factors for Use with ASCE 7-05 Method 1 Wind Design.





Table Design Aid 4.11.7 Site Classifications and Coefficients.





Table Design Aid 4.11.8 Design Coefficients and Factors for Precast Concrete

Seismic-Force-Resisting Systems.

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design of multi level car park using pre- cast/pre...

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