采用拉索模数伸缩缝的斜交桥地震易损性分析

Seismic Fragility Analysis of Skew Bridges with Cable-Slide Modular Expansion Joints

为了研究拉索模数伸缩缝对一座30°斜交角的三跨混凝土斜交连续梁桥抗震性能的影响,利用理论易损性分析方法分析了脉冲地震动和无脉冲地震动作用下拉索模数伸缩缝的减震效果,并提出了以震后维修费用曲线评价桥梁结构体系抗震性能的方法。结果表明,采用拉索模数伸缩缝后桥墩和支座的易损性均显著降低;速度脉冲效应不会改变结构的破坏模式,但对于采用拉索模数伸缩缝的斜交桥,速度脉冲效应会显著增加支座和桥墩的易损性;无论是脉冲地震动还是无脉冲地震动作用下,采用拉索模数伸缩缝均能有效减小斜交桥的震后维修费用。

In order to investigate the influence of slidingcable modular expansion joints on the seismic performance of a three-span concrete skew continuous beam bridge with a 30°skew angle,sliding-cable modular expansion joints are adopted to restrict the rotation of skew bridge girders,the seismic performance of the skew bridge equipped with sliding-cable modular expansion joints in pulse-like and no pulse-like ground motions is explored using analytical fragility curves,and the postearthquake repair cost curve is proposed to evaluate the seismic performance of bridge structures.The results show that the fragility of piers and bearings is significantly reduced after cable-sliding modular expansion joints are adopted.Under the influence of velocity pulse effect,the fragility of both skew bridge bearings and piers with cable modulus expansion joints significantly increase but the structure failure mode remains the same,and the use of cable-sliding modular expansion joints effectively reduces the seismic repair cost of the bridge regardless of whether ground motions are pulse-like or not.