This section provides the basic instructions on how to model, analyze and design the Steel I Girder Bridge using OpenBrIM.App.

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The finalized version of the example steel I girder bridge model, displayed in the screenshot below, can be accessed in the example projects section under the new project UI.
Users have the option to start from scratch and follow a step-by-step guide to model, analyze, and design superstructure and substructure components of the bridge. Furthermore, a comprehensive set of bridge inputs is available for easy copying and pasting into the OpenBrIM.App DATA spreadsheet.

Open

3D Model

Design Parameters

Specification : 2020 AASHTO LRFD Bridge Design Specification, U.S. Units, Ninth Edition

Structural Steel : AASHTO M270, Grade 50 (ASTM A709, Grade 50) steel with Fy=50 ksi, Fu=65 ksi

Concrete : f’c=4 ksi, γ=150 pcf

Slab Reinforcing Steel : AASHTO M31, Grade 60 (ASTM A615, Grade 60) with Fy=60 ksi

Span Length : 160 ft - 210 ft - 160 ft

Radius of Bridge : 700 ft

Deck Width : 40.5 ft

Deck Thickness : 9 in

Integral Wearing Surface : 0.5 in

Haunch Thickness : 4 in

Lane Width : 12 ft

Superelevation : %5

Design Loads

Future Wearing Surface : 30 psf

SIP : 15 psf

Live Load : HL-93 Design Vehicle

Fatigue : 75-year life
Single-lane average daily truck traffic (ADTT)sl - 1000 Trucks per day

Steel I Girder Bridge workflow enables you to:

• Generate a 3D model of a Steel I Girder Bridge, incorporating both substructure and superstructure parametrically, and export it to dgn/dxf/ifc files.

• Create a parametric FEA model.

• Apply loads for FEA:

  • Wind Load on Structure from various attack angles, based on AASHTO specifications. Users do not need to modify wind load data when the structure's geometry changes. They only need to enter gust effect factor, drag coefficients, surface roughness, and design wind speed. OpenBrIM Wind Load Library automatically calculates nodal loads based on these inputs and the structure's geometry for different attack angles.

  • Wind load on live load from various attack angles based on AASHTO specifications.

  • Influence surface-based braking/centrifugal/live loads, including HL93, Legal Truck, Permit Trucks, etc. Users can also define custom trucks.

  • Temperature loads.

  • Surface/Line/Point loads on different structural elements.

  • Tendon stressing for substructure components.

• Create Staged Construction Model:

  • Girder erection sequence.

  • Deck pouring sequence in transverse and longitudinal directions.

  • Deconstruct deck/girder/substructure/barrier for rehabilitation projects in transverse and longitudinal directions.

  • Add/remove temporary supports.

• Run time-dependent staged construction analysis in your web browser.

  • OpenBrIM.FEA considers the non-composite and composite states of girders based on user-defined definitions during the construction stages.

  • OpenBrIM.FEA supports modulus of elasticity override within stages, which is important to include short-term and long-term modulus of elasticity of the deck based on AASHTO.

  • OpenBrIM.FEA supports influence surface-based live load analysis. Influence coefficients are generated after capturing the structure's stiffness at that particular stage. This feature is helpful for rehabilitation projects where the structure's stiffness changes at different stages and the bridge is open to traffic. Critical vehicle placement follows AASHTO rules, considering factors like multiple presence, impact factor, and minimum back-to-front axle spacing. Critical transverse lane placement is automatically done by OpenBrIM, and the user only defines the roadway.

  • OpenBrIM.FEA supports time-dependent staged construction analysis to evaluate deck and substructure creep and shrinkage according to CEB-FIP 1990.

  • OpenBrIM.FEA calculates both short-term losses (such as anchor set, wobble coefficient, and curvature friction of tendons) and long-term losses (including elastic shortening, creep-shrinkage, and relaxation) of tendons.

• View time-dependent staged construction analysis results in your web browser.

  • Examine the results of each stage, observing both the incremental and cumulative effects. You can filter the results at each stage based on their load type.

  • Visualize deflections graphically and access them in spreadsheet format.

  • Review combination results for various limit states.

  • Access composite results, which are crucial when dealing with composite girders consisting of multiple elements. These results allow for the combination of forces at the center of gravity of the composite section.

  • Analyze stress distributions.

  • Visualize the precise location of the critical vehicle for each result for the influence surface based live load analysis.

• Export the finite element model to LARSA 4D, CSI Bridge, or Midas software to compare the results with those obtained from OpenBrIM.FEA.

• Design substructure and superstructure components according to AASHTO 9th Edition and DOT amendments. The following components are supported for design:

  • Steel I Girder

  • Splices

  • Cross Frames

  • Cross Frame Gusset Plates

  • Shear Studs

  • Pier Caps

  • Pier Columns

  • Pier Footings

  • Piles

  • Drilled Shafts

• Load Rate Steel I Girders according to AASHTO 9th Edition and Manual For Bridge Evaluation.

• In your summary report, you can access additional reports for the following items:

  • Camber Diagram

  • Quantity Report

  • Seat Elevation Table

  • Slab Elevation Table

  • Project Inputs

  • Vertical Clearance Report

• Generate parametric 2D drawings from your model and export to dgn or dxf. You can link the exported drawings to your project-wise folder and add additional annotations, among other things, using Microstation.

   

With this workflow, whenever you modify a bridge component parameter or alignment, all associated results/reports will be automatically updated, and you can view them within minutes. This showcases the power of parametric bridge engineering in the OpenBrIM Platform.