考虑支座硬化与碰撞的隔震结构易损性分析

Fragility analysis of isolation structures considering the hardening and collusion of bearings

支座硬化以及隔震层与周围挡土结构的碰撞导致增量动力分析曲线发生突变,针对这一问题提出了适用于同时考虑支座硬化和结构碰撞的地震需求模型。选取21条地震动记录,对隔震结构进行增量动力分析及易损性分析。通过一个21层框架-剪力墙结构的实际工程算例,应用所提出的模型,研究地震作用下隔震沟宽度对结构动力响应及易损性的影响。研究结果表明:碰撞后结构虽然隔震层位移减小,但会造成楼层峰值加速度明显放大及隔震效果的减弱。在发生硬化和碰撞时,滞回圈均会出现明显的上翘现象,IDA曲线会出现突变。在极罕遇地震作用下,当隔震沟宽度较大时,基础隔震结构上部结构出现损伤的超越概率比隔震沟宽度较小的结构均有所减小,其中出现严重损伤的概率减小了17.17%,出现破坏的超越概率减小了3.50%。

Bearing hardening and collision between isolation layer and surrounding retaining structure lead to abrupt change of incremental dynamic analysis curve.To solve this problem,a seismic demand model for bearing hardening and structural collision is proposed.Twenty-one ground motion records were selected to conduct incremental dynamic analysis and vulnerability analysis of isolated structures.Based on a practical engineering example of a 21-story frame-shear wall structure,the proposed model is applied to study the effect of the width of isolation ditch on the dynamic response and vulnerability of the structure under earthquake action.The results show that although the displacement of isolation layer decreases after collision,the peak acceleration of the floor is obviously amplified and the isolation effect is weakened.When hardening and collision occur,the hysteresis loop will appear obvious upwarping phenomenon,and IDA curve will appear abrupt change.Under the action of rare earthquakes,when the width of isolated ditch is larger,the transcendence probability of damage occurring in superstructure of base isolated structure is lower than that of structure with small isolated ditch,in which the probability of moderate damage is reduced by 17.17%,and the transcendence probability of serious damage is reduced by 3.50%.