Pratt Truss Bridge

Application ID: 8511


This example is inspired by a classic bridge type called a Pratt truss bridge. You can identify a Pratt truss by its diagonal members, which (except for the outermost ones) all slant down in span-wise direction towards the bridge’s center. All the diagonal members are subject to tension forces only, while the shorter vertical members handle the compressive forces. Since there is no buckling risk in the tension-loaded diagonal members, they can be thinner resulting in an overall more economic design.

A truss structure supports only tension and compression forces in its members and you would normally model it using bars, but as this model uses 3D beams it can also to some extent sustain bending moments in the frame structure. In the model, shell elements represent the roadway.

This model example illustrates applications of this type that would nominally be built using the following products: