Seismic Fragility Analysis of Cable stayed Bridges Retrofitted with Cable sliding Friction Aseismic Bearing

Abstract:

Seismic response analysis was carried out for the cable stayed bridge with or without cable sliding friction aseismic bearing (CSFAB) on the basis of the probabilistic seismic demand model (PSDM). Fragility curves were obtained for both the bending moment of the tower and the pier girder relative displacement. A comparative study of the fragility curves shows that the CSFAB can reduce the pier girder relative displacement effectively and mitigate the bending moment at the tower base as well. The investigation result of the aseismic mechanism of the cable stayed bridges reveals that adding damping from friction and changing seismic force transferring path by the elastic cables are two main reasons for reducing seismic response of the cable stayed bridges.

Key words:cable stayed bridges; cable sliding friction aseismic bearing (CSFAB); probabilistic seismic demand model; fragility curve