Seismic analysis of stone arch bridges collapsing under earthquake

Nonlinear dynamic analysis of a number of Iranian stone masonry railway bridges is implemented using the distinct element method (DEM) to estimate the seismic capacity of the same bridges. For the study, three stone bridges of the Iran railway system are studied under some important earthquakes. The bridges are studied for their nonlinear dynamic behavior up to total collapse in the transverse direction with an incremental dynamic analysis using suitably magnified earthquake records. The results of the DEM model exhibit a good resemblance with the experimental findings. This study shows that the arches of the studied bridges are the most vulnerable parts of the bridge structure. It is observed that even with strengthening only the arches a considerable enhancement is achieved in the seismic capacity of stone arch bridges.