ABSTRACT
ABSTRACT: As the concept of seismic design is shifting from elastic design to limit state design, new analysis tools which can consider inelastic behaviors of the cable-stayed bridge under earthquake loads are necessary. In this study, the inelastic model of the Second Jindo Bridge, which can consider material nonlinearity as well as geometric nonlinearity, is investigated to define the ultimate behavior of the structure under earthquake loads and perform the nonlinear analysis. From the time history dynamic analysis with four different ground motions which are El Centro, Kobe, Taft, and Mexico earthquake, the analyses prove that responses of the bridge depend on not only peak acceleration but also other variables such as frequency characteristics and the duration time. Furthermore, the static push-over analysis of steel pylon shows that an unexpected local buckling, which can not be predicted in the inelastic beam analysis, could happen and lead to the sudden collapse of the cable-stayed bridge. Therefore, the new seismic capacity estimation method of the cable-stayed bridge that can take into account the local bucking effect of the steel pylon using the inelastic beam element is proposed. In addition, a seismic reinforcement method is suggested by filling the steel pylon with the concrete. From the experimental work this reinforcement method is concluded as an effective method.
