Seismic reliability of a cable-stayed bridge retrofitted with hysteretic devices

This study evaluates the fragility curves of a cable-stayed bridge by an analytical approach based on time history analysis. The presentation of the vulnerability information in the form of fragility curves is a widely practiced approach when several uncertain sources are involved. The ASCE benchmark problem of a cable-stayed bridge is considered as a case study. A passive control technique is adopted and results are compared in term of fragility curves. In order to consider the uncertainties related to the ground motion 24 ground motion time history are considered, corresponding to four different hazard levels, while the uncertainties in the structural characteristics are introduced by defining the different performance thresholds as random variables. The fragility evaluation shows how important a correct estimation of the limit state is for the comparison of different retrofit techniques.