【摘要】 为促进基于性能的概率性抗震评估方法在中等跨径混凝土斜拉桥中的应用,以一实际工程为例,建立了有限元动力分析模型。结合快速非线性分析(FNA)和增量动力分析(IDA)的优点,从PEER强震数据库中选取13条远场地震波进行快速增量动力分析(FNIDA),采用非参数统计方法形成了16%,50%和84%三种概率水平的IDA分位曲线。基于桥址处的地震危险性曲线建立了算例桥梁的概率地震风险评估曲线,并根据《公路桥梁抗震设计细则》对其抗震性能和抗震风险进行了分析。研究结果表明:FNIDA方法能很好地解决传统IDA方法在斜拉桥抗震分析中计算量大和耗时多的缺点;纵桥向地震作用下支座最易破坏,横桥向地震作用下挡块最易破坏,且塔底截面横桥向的抗震能力也有待加强;所提出的概率性风险评估曲线可直接用于斜拉桥结构的抗震性能评估。更多还原

【Abstract】 To popularize the application of the performance-based probabilistic seismic assessment method for medium-span concrete cable-stayed bridges,a bridge was taken as a case-study to establish the nonlinear finite element model.The advantages of the fast nonlinear analysis(FNA)and the incremental dynamic analysis(IDA)were considered to propose the fast nonlinear incremental dynamic analysis(FNIDA).From the ground motion database,13far-fault ground motions were selected for nonlinear analysis.The nonparametric statistic method was applied to develop the fractile IDA curves at three probability levels,16%,50% and 84%. The probabilistic seismic risk assessment curves were established based on the seismic hazard curves of the bridge site.Then,the seismic performance and seismic risk of the bridge were estimated according to the Seismic Design Guidelines of Bridges of China.The results show that the FNIDAmethod can overcome the problems of great amount of calculation and time-consuming with the traditional IDA method.In the longitudinal direction,bearings are the most vulnerable components.In the transversal direction,the shear key shows significant vulnerability and the bottom section of the concrete tower needs to be retrofitted.Probabilistic seismic risk curves can be directly applied to the seismic evaluation of the cable-stayed bridges.更多还原