ABSTRACT
This work concerns the large-scale study of the seismic vulnerability of girder railway bridges in relation to the level of the acquired knowledge (complete or partial). The seismic vulnerability of such infrastructures is estimated using fragility functions. A detailed modeling has been developed for bridges with complete knowledge of the data. A finite element model of the bridge in which non-linear behavior occurs for piers and supports has been developed. Fragility curves are obtained by performing several time history analyses based on the selected return periods, i.e. 9 in agreement with Italian technical standards (D.M. 17/01/2018) using spectrum-compatible accelerograms. In the case of partial knowledge a simplified procedure for seismic evaluation for girder bridges based on displacements is used. Each pier-support subsystem is considered through a SDOF equivalent system, for each return period the probabilities of exceeding the limit states have been calculated and then the fragility curves is calculated.
