设置钢管灌浆阻尼器的RSC双层排架墩抗震性能分析

Seismic Performance Analysis of RSC Double-deck Bridge Bent with Steel-tube Grout Damper

为实现双层桥梁排架墩地震损伤控制设计,提出上层排架采用摇摆-自复位(Rocking Self-Centering,RSC)体系、下层排架不摇摆的双层桥梁排架墩设计思路,并采用钢管灌浆阻尼器(Steel-tube Grout Damper,SGD)提升摇摆接缝处的耗能能力。基于OpenSees数值分析平台分别建立了SGD和外置SGD的RSC双层排架墩抗震数值分析模型,结合试验结果验证了SGD和RSC排架墩建模方法的准确性。选取7条近断层地震动记录,基于增量动力分析(Incremental Dynamic Analysis,IDA)手段,研究外置SGD的RSC双层排架墩的地震反应。研究结果表明,当PGA为0.1 g时,SGD开始屈服耗能;当PGA为0.4 g时,SGD最大变形为名义极限变形的53.44%,无粘结预应力筋最大应力为名义屈服强度的59.60%;当PGA为0.8 g时,SGD接近拉断,预应力筋最大应力为名义屈服强度的84.78%;与耗能角钢相比,SGD变形及耗能能力更强,在强震作用下更不易发生拉断破坏。

A new design method for double-deck bridge bents was proposed to achieve seismic damage control.This method incorporates a rocking self-centering(RSC)structure for the upper-floor piers,while the lower-floor piers remain non-rocking.Additionally,steel-tube grout dampers(SGDs)are used to enhance the energy dissipation capacity of the joints.Numerical analysis models for the seismic behavior of the SGD and the RSC bent with SGD were developed using the OpenSees platform,and their accuracy was verified by comparing them with test data.Seven near-fault ground motions were selected,and incremental dynamic analysis(IDA)was conducted to study the seismic behavior of the bent.The study results indicate the following:(1)When the peak ground acceleration(PGA)is 0.1 g,the SGD yields and dissipates energy.(2)At a PGA of 0.4 g,the maximum deformation of the SGD is only 53.44%of the nominal ultimate maximum deformation,and the maximum stress of the unbonded prestressing tendons is 59.60%of their nominal yield strength.(3)When the PGA reaches 0.8 g,the SGD is close to rupture,and the maximum stress of the prestressing tendons is 84.78%of their nominal yield strength.Compared to steel angles,SGDs exhibit greater deformation and energy dissipation capacity and are less prone to rupture damage under strong earthquakes.