强震作用下减隔震桥梁抗震性能试验研究

Experimental Study of Seismic Performance of Seismically Mitigated and Isolated Bridges Under Strong Earthquake

为了研究连续梁桥的地震反应特性,对一座采用铅芯橡胶支座的三跨连续梁桥结构进行振动台试验。按峰值加速度从小到大的顺序依次输入El-Centro波、拟合波、人工波3种地震波,研究结构的地震反应,并对比边墩、中墩的地震反应,分析墩柱损伤对支座减隔震性能的影响。结果表明:地震波峰值加速度小于0.3g输入时,结构整体地震反应较小,处于弹性工作状态,地震波峰值加速度0.3g^0.5g输入时,结构整体地震反应逐渐增大,形成塑性铰,地震波峰值加速度0.6g输入后,结构达到承载能力极限状态,发生破坏;连续梁桥中间墩的地震反应略小于边墩;桥墩塑性破坏后的刚度退化会限制支座减隔震作用的发挥,但同时墩柱刚度退化也会有效延长结构自振周期,降低结构的地震反应。

To study the seismic response characteristics of continuous girder bridges ,the shake table tests for a 3‐span continuous girder bridge structure using the lead‐rubber bearings were made .3 kinds of the seismic waves of the El‐Centro wave ,fitted wave and artificial wave were suc‐cessively input in the tests in the order of the high to low peak acceleration and the seismic respon‐ses of the structure were investigated .The seismic responses of the side and central piers were compared and the influences of damage of the pier columns on the seismic mitigation and isolation performance of the bearings were analyzed .The results demonstrate that when the peak accelera‐tion of the seismic waves that is less than 0 .3g is input ,the global seismic responses of the struc‐ture are weak and the structure is in the state of elasticity .When the peak acceleration of 0 .3g-0 .5g is input ,the global seismic responses of the structure gradually increase and the plastic hin‐ges come into being and w hen the peak acceleration of 0 .6g is input ,the structure reaches the limit state of the bearing capacity and the damage takes place .The seismic responses of the central piers of the continuous girder bridges are slightly w eaker than those of the side piers .T he rigidity dete‐rioration of the piers after the plastic damage restricts the role of the seismic mitigation and isola‐tion of the bearings ,however ,the rigidity deterioration of the pier columns will effectively prolong the natural vibration periods and decrease the seismic responses of the structure at the same time .