适用于中小跨径梁桥的组合橡胶支座减震性能

Seismic Performance of Composite Rubber Bearings for Small-and-Medium-Span Bridges

中小跨径梁桥常用的板式橡胶支座位移能力不足,地震中容易发生支座滑动,导致墩梁相对位移过大。为此提出一种新型组合橡胶支座,支座截面由叠层区和滑动区组成,支座内部能够发生滑动从而减小水平刚度、提高位移能力并耗散地震能量。对6块支座试样开展了拟静力试验探究压力、胶料性能、滑动区刚度占比的影响,并选择典型简支梁桥进行有限元分析,对比了组合橡胶支座和板式橡胶支座的地震响应。结果表明,组合橡胶支座等效刚度小、位移和耗能能力强,能够避免支座滑动,并显著减小支座位移和桥墩弯矩。

Laminated rubber bearings are commonly used in small-and-medium-span girder bridges but they lack in displacement capacity and are likely to slide in earthquakes,which results in excessive relative displacements between piers and girders.Thus,a new type of composite rubber bearing,of which the cross section is composed of a laminated area and a sliding area,is proposed in this paper.Interior sliding is allowed to reduce the horizontal stiffness,improve the displacement capacity,and dissipate the seismic energy.Quasi-static tests were conducted for six bearing specimens to study the effects of pressures,rubber properties,and sliding area stiffness ratios on the bearing performances.Finite element analyses were performed based on a typical simply supported girder bridge.The seismic responses of composite rubber bearings and laminated rubber bearings were compared.The results show that the composite rubber bearings possess a small equivalent stiffness,strong displacement and energy dissipation capacities.Total sliding of bearings can be effectively avoided and both bearing displacements and pier moments can be significantly reduced in earthquakes.