桥梁地震响应半主动控制的加速度放大效应

采用磁流变阻尼器,对1座大跨刚构连续梁桥进行半主动控制、主动控制和被动控制地震响应计算,比较分析6种半主动控制算法对桥梁加速度的放大效应。结果表明:当磁流变阻尼器设置在桥梁支座等连接构件处时,不同半主动控制算法会使阻尼器附近桥梁局部位置的加速度产生不同程度的“针尖”放大效应,而主动控制和被动控制不会产生这种加速度放大效应;比较而言,“开关型”半主动控制算法比“连续型”半主动控制算法的加速度放大效应更加严重;半主动控制算法引起的桥梁加速度放大效应与阻尼器类型、阻尼器位置和桥梁结构动力特性等多种因素有关;半主动控制算法对桥梁的位移和弯矩不会产生剧烈放大的“针尖”现象;阻尼器设置在墩梁刚性连接部位时不会出现加速度放大效应。

Acceleration Magnified Effect on Seismic Response of Semi-Active Control for Bridge

The semi-active control,active control and passive control analysis of seismic responses for a long-span rigid-continuous beam bridge is performed with magnetorheological dampers.The acceleration magnified effects of the six semi-active control algorithms for bridge are analyzed and compared.Results indicate that when the magnetorheological dampers are set at the positions of bridge link components including bearings,the different semi-active control algorithms can produce various degrees of "needlepoint" magnified effect for acceleration at the local positions of bridge nearby the dampers.Active control and passive control can not produce this acceleration magnified effect.The acceleration magnified effect of the "switch type" semi-active algorithms is more severe than that of the "continuous type" semi-active algorithms.This acceleration magnified effect caused by semi-active control algorithms relates to many factors including types of dampers,locations of dampers and kinetic characteristics of bridge.Semi-active control algorithms can not cause the severely magnified "needlepoint" phenomenon for moment and displacement of bridge.The acceleration magnified effect is not caused when dampers are set at locations of rigid connection of pier and beam.