地震作用下隔震简支梁桥碰撞反应的振动台试验

Shaking table test on pounding responses of simply supported isolated bridges under earthquake excitation

由地震引发的碰撞是影响桥梁地震反应以及造成桥梁破坏的重要因素。本文对地震作用下隔震简支梁桥的碰撞反应进行了振动台试验。设计制作1个两跨简支的隔震梁桥模型,试验研究了梁间隙、邻梁质量比、隔震支座类型等参数对桥梁碰撞反应的影响。试验结果表明邻梁间隙、邻梁质量比、隔震支座类型等参数对桥梁的碰撞反应有着显著的影响。邻梁间隙越大,碰撞次数越少;邻梁质量比越大,撞击力越大。铅芯橡胶支座比板式橡胶支座耗能能力更强,可以有效降低邻梁之间的撞击力甚至避免碰撞发生。从而为桥梁防碰撞设计提供了可靠的试验依据。

Seismic pounding has significant influence on the seismic responses of bridges and maybe is the critical factor causing the damage to some bridges. A shaking table test on pounding responses of simply supported isolated bridge is done. A two-span simply supported isolated bridge model is designed firstly, and the influences of gap, mass ratio of adjacent girders and properties of isolated bearing on the pounding responses of the bridge are investigated. Testing results show that the parameters, including gap and mass ratio of adjacent girders and properties of isolated bearing, have significant effects on the pounding responses of bridges. The bigger the gap of the adjacent girders is, the lower the frequency of pounding becomes. The larger the mass ratio of adjacent girders is, the larger the impact force becomes. The lead rubber bearing has higher capacity of energy dissipation than the plate rubber bearing, and may reduce the impact force between the adjacent girders or even avoid the occurrence of the pounding of bridges. This provides a reference for pounding prevention design of bridges.