Automatic procedure for fragility assessment of common existing road bridge typologies

Road bridges are the most vulnerable elements in existing road networks during earthquakes. One the most diffused methods for the seismic vulnerability assessment of existing bridges is based on the calculation of fragility curves, giving the probability of a bridge reaching a certain damage state for a given ground motion parameter. This study describes an automatic procedure based on OpenSEES and MATLAB to calculate analytical fragility curves for common existing road bridges typologies. The related application allows to build a 3-D analytical model of the bridge by simple input data windows, upload a set of selected ground motions and automatically calculate analytical fragility curves by means of non linear dynamic analyses (NLDAs). This instrument can be a useful and performing tool for Road Managing Authorities to properly assess the seismic vulnerability of bridges in their road networks.