psc box girder design aashto lrfd

Bridging Your Innovations to Realities

02

03

15

19

24

Introduction

Modelling

Analysis Control

Design

Other features

MIDAS Information Technology Co., Ltd. 2

Bridging Your Innovations to Realitiesmidas Civil Introduction

Cable stayed bridge & Extra-dosed bridge

Staged segmental post-tensioned bridge

Curved steel plate and composite girder bridge

Conventional bridge (Skewed slab, Frame & Culvert)

Suspension bridge

Application Areas

Integral bridge

Subway structure

Tunnel structures

Sewage treatment plant

Heat of hydration for mass concrete

Advanced Technology


02

03

15

19

24

Introduction

Modelling

Analysis Control

Design

Other features


Modelling Philosophy

midas Civil Modeling Features

1. Line Beam a fairly crude tool does not take account of transverse distribution gives no output for transverse design does not consider skew effects. Useful tool for the preliminary design Inappropriate in wide and skew bridges For narrow bridges accurate results can be

obtained in a faster way

2. Grillage• Involves idealization of bridge deck through grillage

of interconnected beams• Rigidly connected longitudinal and transverse

beams each with bending and torsional properties• Accurate Load distribution• Accurate Bearing Reactions

3. Full Finite Element Model• More realistic structural response

• Accurate representation of local and global

responses.

• Models can be built using combination of plate

and beam elements

There are three modelling options for a typical bridge:

• Line beam

• Grillage

• Full Finite Element Model


Methods of modelling


Modeling of a Bridge in midas Civil can be done by:

General Modeling Procedure Using wizards

ILM BridgeFCM BridgeFSM BridgeSuspension BridgeCable Stayed BridgeRC Frame/BoxRC Slab Bridge

Grillage Wizard Transverse Section Wizard

Wizards are extremely useful when bridge is constructed through the typical construction process. Forother types of bridges midas Civil provides user friendly intuitive interface that enables quick and accuratemodelling.


FCM Bridge Wizard (Free Cantilever Method)


Model -> Structure Wizard -> FCM Bridge


FSM Bridge Wizard (Full Shoring Method)


Model -> Structure Wizard -> FSM Bridge


PSC DB Sections


The following types of PSC sections can be defined: n cell sections PSC I sections PSC T sections

Database sections: AASHTO (Type I to Type VI)

Caltrans sections Italy UK

User Defined ShapeSection Property CalculatorGeneral Section Designerdxf file

Model -> Properties -> Section -> PSC section


PSC Sections – Tapered Sections


Tapered Sections for PSC Bridges:

2. Tapered Section Group:

Model -> Properties -> Tapered Section GroupIt automatically calculates the sectional properties of the non-prismatic section such that the group section varies uniformly

irrespective of the number of segments in the group.

1. Tapered Section Tab:

Model-> Properties -> Section -> Tapered TabThe sections can be defined in tapered section tab or the Sections can be defined in the PSC tab and imported as I and J end of the tapered section.


PSC Sections – Tapered Sections


Tapered Sections for PSC Bridges:

2. PSC Bridge WizardModel-> Structure Wizard -> PSC Bridge -> Section & Reinforcement

This feature obviates the use of the tapered section and the depth of the section be directly defined in the longitudinal direction of the bridge.

With PSC bridge wizard not only the depth but the width, web thickness and flange thickness can be varied.


Tendon Profile Definition


Tendon Profile can be defined in 2D and 3D as per the following reference axis:

Straight Curve Element

Straight: the x-direction (the reference line from which tendon coordinates are defined) of TCS for tendon placement is consideredas a straight line.

Curve: the x-direction (the reference line from which tendoncoordinates are defined) of TCS for tendon placement is considered as a curved line.

Element: Tendon location is converted into Element Coordinate System and applied.


Tendon Profile Export/Import with dxf


The tendon can be exported/imported with AutoCAD in midas civil:

2. Import: For importing the tendons from the AutoCAD, the tendon profile generator is used.

The following steps must be followed: 1. Tools-> Tendon Profile Generator 2. Open the dxf file in which the tendon profile is defined3. Select the tendon profile and define the required

parameters 4. Click –> Add5. Click -> Ok, the text file will be generated6. Copy the contents of the text file and paste to MCT

and then hit run.

1. Export: For exporting the tendon, select the tendon in the Tendon definition dialogue box and then hit export to dxf.


Negative Moment at Joints



Effective Width Scale Factor


Effective Width Scale Factor:

Effective Width Scale Factor can be used to consider the effect of shear lag

The effective width scale factor can be defined by: 1. Automatic definition: The automatic definition of the Effective width scale factor is supported for

AASHTO LRFD code and can be defined in PSC Bridge wizard2. Manual definition: The manual definition of the effective width scale factor can be done in effective width

scale factor as the boundary


02

03

15

19

24

Introduction

Modelling

Analysis Control

Design

Other features

Bridging Your Innovations to Realitiesmidas Civil Analysis Control

Tendon Tension Loss Effect


Stress Decrease at Lead Length Zone

Select a method of computing stresses over a transfer length in a post-tension model. This feature is applicable only when a Transfer Length is entered in the Tendon Profile dialog.

If Composite section for Construction Stages is used this function cannot be applied.

tendon

Transfer Zone


Change of Beam Section Properties with Tendons

Select whether to consider the presence of tendons for calculating section properties.


02

03

15

19

24

Introduction

Modelling

Analysis Control

Design

Other features


Limit States

midas Civil Design

Ultimate Limit State :• Check Flexure Strength• Check Shear Strength• Check Combined Shear and Torsion Strength

Serviceability Limit State:• Check Stress for Cross Section at Construction Stage• Check Tensile stress for Prestressing Tendons• Check Tensile Stress for Cross Section at Service Loads• Principal Stress at Construction Stage• Principal Stress at Service Loads• Principal Stress at Service Loads (excluding Torsional Shear Stress)• Check Crack Width at Service Loads


Flexure Design

midas Civil Design

Aps

A’s

dp

Strain

ds

ca=β1c

d’s 0.003

εps

ε's

f's

fps

fs

0.85f’c

Stress

Cc

ac Strain Variation and

Stress Distribution

in a Section

Calculation of Nominal Moment

Capacity for a Flanged and a

Rectangular Section


Shear Design

midas Civil Design

MIDAS Information Technology Co., Ltd. 23

Bridging Your Innovations to Realitiesmidas Civil Design

Pier Design


02

03

15

19

24

Introduction

Modelling

Analysis Control

Design

Other features

Bridging Your Innovations to Realitiesmidas Civil

1. Transverse Analysis Model

Other Useful features

The following steps must be performed for the same: 1. Selecting the required element for generating the transverse analysis model 2. Defining the parameters such as loads and reinforcement.3. Defining the moving load parameters 4. Opening the generated model

Transverse analysis wizard can be used to perform the transverse analysis by selecting a section from the bridge


2. Full 3D modeling in midas FEA

Warping Effect Check and 3D Finite Element Modeling in FEA

Midas Civil and Midas FEA can be used in tandem with each other for performing global and detailed analysis.

Midas Civil model can be exported to FEA for generating the solid model and meshing and detailed analysis can be performed.

Other Useful Features


3. Grillage Model Wizard



4. FCM Camber

FCM Camber: In structural design, camber refers to a pre-fabricated / pre-designed shape which enables the members maintain a stress-free state in order for the member to reach a targeted shape at a specified time.


midas Civil 29

psc box girder design aashto lrfd

Documents

typical bridge

bridge extradosed bridge

realitiesfsm bridge

realitiespsc sections

group section

idealization of bridge

tapered section groupit

tapered section tab