Seismic assessment of a curved multi-span simply supported truss steel railway bridge

Abstract

Fragility curve is an effective method to determine the seismic performance of a structural and nonstructural member. Fragility curves are derived for Highway Bridges for many studies. In Turkish railway lines, there are lots of historic bridges, and it is obvious that in order to sustain the safety of the railway lines, earthquake performance of these bridges needs to be determined. In this study, a multi-span steel truss railway bridge with a span length of 25.7m is considered. Main steel truss gird-ers are supported on the abutments and 6 masonry piers. Also, the bridge has a 300m curve radius. Sap 2000 finite element software is used to model the 3D nonlinear modeling of the bridge. Finite element model is updating according to field test re-cordings. 60 real earthquake data selected from three different soil conditions are considered to determine the seismic performance of the bridge. Nonlinear time his-tory analysis is conducted, and maximum displacements are recorded. Probabilistic seismic demand model (PSDMs) is used to determine the relationship between the Engineering Demand Parameter (EDP) and Intensity Measure (IMs). Fragility curve of the bridge is derived by considering the serviceability limit state, and results are discussed in detail.