LARSA 4D's Steel Bridge Module uses a wizard-like interface to simplify 3D model generation for complex I, box, and tub girder bridges, while providing fully integrated AASHTO compliant code check and load rating tools, along with the ability to move beyond typical grillage analysis to utilize influence surface based live load.
Analysis results from the bridge model are automatically processed to perform AASHTO LRFD compliant code check. Checks are performed for strength, serviceability, fatigue, constructability, live load deflection, cross-frames and substringers.
Using the results gathered from the influence-surface based analysis, the equations and values used in the rating are reported, and rating factor results are displayed for the selected live loads. Rating provides the flexibility to use any 2D, permit, or custom defined vehicle.
To more accurately capture the extraction of lateral bending moment, girders can be modeled as line elements representing the web and flanges together, or as a composition of plate and shell elements for the web and line elements for the flanges.
Through a wizard-like interface, the module uses four task-based steps to collect the information necessary to generate the 3D bridge model, which is brought into LARSA 4D's main environment supporting full production and access to advanced features.