Fragility Curve Analysis of Medium Cable Stayed Bridge

Abstract

The seismic performance of a bridge can be shown by analyzing the vulnerability of the structure in resisting an earthquake motion and then developing into fragility curves. This study presents a convenient method to establish the fragility curve for the cable-stayed bridge. For this purpose, three spans cable-stayed bridge is assessed using a series of seismic loads in different intensities to ensure that the structure was experiencing damage in several conditions. The fragility curve was obtained by analyzing the structure using Nonlinear Time History (NTHA) and Pushover Analysis. The ground motions of the earthquake were subjected to the bridge in different intensities, which were scaled from the initial ground motion. Hereafter, the structure’s ductilities were developed into the fragility curves as the responses of the bridge. HAZUS standard is used for classifying the damages of the bridge, which are grouped into; slight, moderate, extensive, and complete due to the seismic load. The values of the damage states were generated to the fragility curves using the probabilistic values of the damage states. To ensure the validity of the data statistically, Kolmogorov-Smirnov test was conducted to the fragility function. The result revealed that the fragility curve was qualified as the lognormal distribution.

Keywords

• fragility curves
• cable stayed bridge
• nonlinear time history
• hazus