大跨度斜拉桥耗能型辅助墩抗震性能试验研究

结构损伤控制概念是指通过容易替换的牺牲构件在地震中发生塑性变形耗散地震能量,同时主要构件保持弹性或发生轻微的损伤.针对大跨度斜拉桥的抗震性能主要依靠结构体系的特点,提出了通过牺牲辅助墩耗散地震能量,从而减轻主塔损伤的控制策略.为了研究辅助墩的抗震性能,对3个大比例的钢筋混凝土空心矩形截面模型进行拟静力试验.第一个试件是原设计的单柱墩,另外两个试件是双柱墩,墩柱之间通过耗能构件剪切型连杆或屈曲约束支撑连接.对反复荷载作用下试件的破坏形态、滞回曲线、位移延性和耗能能力、骨架曲线及刚度退化、耗能构件的变形能力等作了对比分析.结果表明,与单柱墩相比,耗能构件增加了双柱墩的刚度和强度,能够提高双柱墩的抗震性能.

Experimental Investigation of Seismic Performance of Energy Dissipation Subsidiary Piers for Long-Span Cable-Stayed Bridges

The concept of structural damage control is that easily replaceable sacrificial elements deform plastically to dissipate seismic energy while primary components remain elastic or are subjected to minor damage. According to that the seismic performance of long span cable stayed bridges depends mainly on their structural systems, a new damage control strategy, namely reducing the damage of the towers by means of sacrificing the subsidiary piers, was proposed. Three large scale reinforced concrete models with rectangular hollow sections were tested under cyclic quasi static loads to investigate seismic performance of the subsidiary piers. The first specimen was a single column pier designed originally, while the others were twin column piers. Shear links (SLs) and buckling restrained braces (BRBs) were installed between the two columns as a series of energy dissipation elements. Failure patterns, hysteretic curves, displacement ductility and energy dissipation capacity, skeleton curves and stiffness degradation of the specimens which were under cyclic loading, and deformation capacity of the energy dissipation elements, were investigated. The results show that compared with the single column pier, the energy dissipation elements increase the stiffness and strength of the twin column piers and improve their seismic performance.