Influence of relevant parameters on seismic vulnerability assessment of bridges

n this work fragility curves for multi-span simply supported reinforced concrete (RC) girder bridges, a common structural scheme in Italy, are calculated by means of RISK-UE method and non-linear dynamic analyses. Fragility curves are considered one of the most performing tools to assess existing bridge seismic vulnerability and they can be used for a proper planning of post-earthquake emergency phase and to define a priority for retrofit interventions. In particular, influence of piers height, piers diameter and deck skew angle on seismic vulnerability assessment is investigated. The main benefit using RISK-UE method, which is based on past earthquakes data (empirical fragility curves), is that fragility curves can be quickly calculated without any seismic analysis, whereas seismic analyses (analytical fragility curves) are usually timeconsuming. Since it is observed that the RISK-UE method is not able to properly estimate the seismic fragility of the structure, a proposal to modify it making a comparison between the two procedures is presented in order to improve the quick seismic assessment of bridges.