外置耗能器与复位器的自复位桥墩抗震性能研究

Seismic Performance of Self-centering Bridge Columns with External Energy Dissipators and Restorers

为发展易于实现损伤控制的摇摆自复位(rocking self-centering,RSC)桥墩,选取防屈曲支撑(buckling restrained brace,BRB)作为外置耗能器,弹簧作为外置复位器,设计外置防屈曲支撑与弹簧的自复位(BS-RSC)桥墩。利用Opensees有限元软件建立BS-RSC桥墩的数值分析模型,并验证模型正确性,分析BRB屈服强度、弹簧刚度及轴压比对BS-RSC桥墩滞回性能的影响;进行动力时程分析,研究不同参数对最大墩顶位移角、残余位移角的影响。研究结果表明:BS-RSC桥墩滞回曲线饱满,BRB可显著提升BS-RSC桥墩的耗能能力,控制弹簧刚度可在不影响整体耗能下控制残余位移;进行动力时程分析,在罕遇地震下,桥墩残余位移角处于低值,最大墩顶位移角随着BRB屈服强度的提高而显著降低,说明BS-RSC桥墩是各构件协调工作、功能明确且具有优秀耗能能力与自复位能力的新型桥墩。

In order to develop rocking self-centering(RSC)bridge columns,which was easy to realize damage control,the buckling restrained brace(BRB)was selected as the exterior energy dissipator and the spring was used as the exterior self-centering device,and BS-RSC piers were designed.Firstly,Opensees finite element software was used to establish a numerical analysis model for BS-RSC bridge piers and the correctness of the proposed model was verified.Then,the effects of BRB yield strength,spring stiffness and axial compression ratio on the hysteresis performance of BS-RSC bridge piers were analyzed,and dynamic time-history analysis was also carried out.Finally,the influence of different parameters on the maximum displacement angle on pier top and residual displacement angle was studied.The research results show that the hysteretic curve of BS-RSC pier is full.BRB can significantly improve the energy dissipation capacity of BS-RSC piers,and control spring stiffness can control the residual displacement without affecting the overall energy dissipation.Under dynamic time-history analysis,it is found that under rare earthquakes,the pier residual displacement angle is at a low value,and the maximum displacement angle on pier top decreases significantly with the increase of BRB yield strength,which indicates that the BS-RSC bridge pier is a new type of bridge pier with coordinated work of various components,clear functions,and excellent energy dissipation capacity and self-centering capacity.