Finite element analysis of truss type steel bridges

Abstract

This work aims towards 3-D finite element analysis of truss type steel bridges using SAP2000 software. Some of the recent bridge failures which happened in Sri Lanka were analyzed using SAP2000 software. Failure loads and failure modes of the failed bridges were compared with the finite element analysis results. Scaled down models of a Pratt type truss bridge were tested in the structural laboratory, and then failure loads and failure modes of the test models were compared with the finite element analysis predictions. Models with portal and without portal were tested separately to see the effect of end portals with the introduction of the lateral load. Scaled down model of a Tied Arch bridge was also tested to observe the failure mode and the test results were also compared with the finite element analysis results. Span vs. tonnage graphs were developed for different truss type bridges, such as Pratt, Modified Warren, Tied Arch, Inverted Arch and the Parker truss, considering them being used by pedestrians and light vehicles. The weights of the existing bridges were also compared with the obtained graphs for some of the selected truss types.