填充式钢管阻尼器性能及在桥梁横向减震中的应用

中小跨径桥梁采用板式橡胶支座时,在横桥向地震作用下起到一定的隔震作用,但是墩梁相对位移偏大,主梁容易与挡块发生碰撞,甚至发生横桥向落梁等严重震害.为提高桥梁横向耗能能力,减小地震作用下主梁的侧向位移,研发了一种填充式钢管阻尼器,阻尼器与板式橡胶支座共同组成了桥梁横向减震系统.地震作用下,板式橡胶支座传递竖向荷载并提供一定的横向位移能力,填充式钢管阻尼器通过塑性变形耗散部分输入的地震能量,可以有效减小墩梁相对位移.首先阐明填充式钢管阻尼器的工作机理,试验研究其滞回性能和失效模式,并提出实用简化分析模型.在此基础上,以一座简支小箱梁桥为例,给出填充式钢管阻尼器主要参数的选取过程,分析了主梁和墩顶位移、桥墩与土-结构相互作用力以及填充式钢管阻尼器和桥梁挡块的滞回性能.结果表明:在地震作用下,填充式钢管阻尼器耗能和变形能力远大于钢筋混凝土挡块,附加填充式钢管阻尼器后,墩梁相对位移明显减小,而墩顶位移和墩底内力等变化不大,附加填充式钢管阻尼器后不会对桥墩、桩基等构件产生不利影响.

Behavior of Zinc-filled Steel Tube Damper and Its Application for Improving Transverse Seismic Performance of Girder Bridges

Laminated rubber bearings used in small and medium span bridges show excellent transverse seismic performance under transverse earthquake excitation; however, the relative displacement of the pier-girder is very large. It is easy for the girder to impact the shear key, and even serious disasters such as girder falling can occur. In order to improve the transverse energy dissipation performance of bridges and reduce lateral displacement of the girder, the zinc-filled steel tube damper was researched. The transverse seismic system of a bridge structure includes laminated rubber bearings and zinc-filled steel tube dampers. The bearings are responsible for the transmission of the vertical load and provides the capacity of transverse displacement under earthquake excitation. The damper dissipates a part of the seismic energy through plastic deformation and efficiently reduces the relative displacement of the pier-girder. In this paper, the working mechanism of a damper is explained, and quasi-static tests are performed to research the hysteretic performance and failure modes. According to the results of the tests, a simplified analytical model of the damper is obtained. Based on the research, taking a simplified multi-box girder bridge as an example, the progress of determining the key parameters of zinc-filled steel tube damper is discussed. The displacement of the girder and pier, the internal force of the pier, the interaction of the soil-structure, and the hysteretic performance of reinforced concrete shear key and zinc-filled steel tube damper were analyzed. The results indicate that the energy dissipation capacity and displacement performance of zinc-filled steel tube damper is superior to that of reinforced concrete shear key. The addition of zinc-filled steel tube damper could significantly reduce the relative displacement of the pier-girder, and the displacement or the internal force of the pier changed slightly. The addition of zinc-filled steel tube dampers will not have any adverse influence on the bridge pier, pile foundation, and other components.