Comparison of simplified and full FEM models for seismic response analysis of steel bridges

The response of a typical simply supported railway steel bridge to seismic excitation along its axial, lateral and vertical direction is determined a) on the basis of a simple one degree of freedom spring-mass model, b) on the basis of a full finite element analysis using the programme SAP IV. In both cases the response spectrum and the corresponding seismic provisions of the Greek Ministry of Environment, Physical Planning and Public Works are employed. The method for constructing simplified one degree of freedom models equivalent to the full finite element models is described. A comparison between the results of the two kinds of models is conducted and practical guidelines are suggested.