地震作用下高架桥结构的脆弱性

Fragility of Viaduct Structure Under Seismic Effect

用能力谱方法和非线性动力分析方法分别建立了高架桥结构的脆弱性曲线。对用两种方法建立的脆弱性曲线进行比较发现:对于保护层混凝土剥落破坏状态,由两种方法分析的结果相差不大;对于纵筋屈曲和倒塌破坏状态,用能力谱方法分析的高架桥结构在给定地面运动强度下的失效概率偏低;用能力谱方法进行分析方便快速,但对于严重破坏状态分析精度较低;在应用非线性动力分析方法时需要对结构进行大量的动力时程分析,但结果精确可靠。

Fragility curves of viaduct structure were developed by capacity spectrum method and nonlinear dynamic analysis method respectively. The ＇comparison between fragility curves got from the two methods shows that there is no remarkable difference for concrete spalling damage state in protection layer, and capacity spectrum method underestimates the failure probability of longitudinal reinforcemcnt buckling and collapse for the viaduct structure under given ground motion intensity. Capacity spectrum method is simple and quick, but it provides low accurate results for severe damage states. In contrast, nonlinear dynamic analysis method can get the accurate and reliable results, but it requires much dynamic time-history analysis for structures.