A Framework for Identification of the Critical Members for Truss Bridges through Nonlinear Dynamic Analysis

This study proposes an integrated and easily applicable framework that considers the dynamic effect of sudden member loss to identify the critical members in steel truss bridges through nonlinear dynamic analysis. Numerical simulations of sudden member removal in truss bridges through nonlinear dynamic analysis requires significant computational resource because of the modeling of truss members by shell or solid elements. The proposed approach simulates both yielding and buckling behavior of truss members following sudden removal of a member by modeling truss members using the Hughes-Liu (H-L) beam formulation in LS-DYNA. The approach was demonstrated to be computationally efficient, while preserving the accuracy of the numerical results. The reliability and accuracy of the modeling using the H-L beam formulation were verified through three examples of varying degrees of complexity. The capability of the proposed approach in identifying critical members was demonstrated through a case study of the Aby Bridge (a simply supported truss bridge that was originally designed as a fracture critical bridge).