psc box girder design aashto lrfd
DESCRIPTION
Psc Box Girder Design Aashto LrfdTRANSCRIPT
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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
Bridging Your Innovations to Realities
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Introduction
Modelling
Analysis Control
Design
Other features
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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
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Methods of modelling
midas Civil Modeling Features
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.
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FCM Bridge Wizard (Free Cantilever Method)
midas Civil Modeling Features
Model -> Structure Wizard -> FCM Bridge
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FSM Bridge Wizard (Full Shoring Method)
midas Civil Modeling Features
Model -> Structure Wizard -> FSM Bridge
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PSC DB Sections
midas Civil Modeling Features
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
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PSC Sections – Tapered Sections
midas Civil Modeling Features
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.
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PSC Sections – Tapered Sections
midas Civil Modeling Features
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.
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Tendon Profile Definition
midas Civil Modeling Features
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.
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Tendon Profile Export/Import with dxf
midas Civil Modeling Features
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.
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Negative Moment at Joints
midas Civil Modeling Features
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Effective Width Scale Factor
midas Civil Modeling Features
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
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Introduction
Modelling
Analysis Control
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Bridging Your Innovations to Realitiesmidas Civil Analysis Control
Tendon Tension Loss Effect
Bridging Your Innovations to Realitiesmidas Civil Analysis Control
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
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Change of Beam Section Properties with Tendons
Select whether to consider the presence of tendons for calculating section properties.
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Introduction
Modelling
Analysis Control
Design
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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
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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
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Shear Design
midas Civil Design
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Bridging Your Innovations to Realitiesmidas Civil Design
Pier Design
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Introduction
Modelling
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Design
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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
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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
Bridging Your Innovations to Realitiesmidas Civil
3. Grillage Model Wizard
Other Useful Features
Bridging Your Innovations to Realitiesmidas Civil
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.
Other Useful Features
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