城市隔震高架桥梁地震反应的半主动控制

研究应用磁流变(MR)阻尼器对隔震连续梁桥邻联相对位移的半主动控制,并采用离线优化与在线自调整相结合进行模糊控制(FLC)。以邻联最大相对位移最小化为目标函数,对基本模糊控制器的隶属函数、量化因子、比例因子进行离线遗传优化;对优化后的模糊控制器的量化因子和比例因子进行在线自调整;数值仿真分析一多跨隔震连续梁桥的简化四自由度体系的半主动控制,比较不同控制方案的控制效果。结果表明,将MR阻尼器安装在上部结构与桥墩之间对桥梁邻联相对位移的控制效果优于将其安装在邻联之间;半主动控制能同时有效控制邻联最大相对位移与支座变形;与普通模糊控制以及仅采用遗传优化的模糊控制相比,具有在线自调整功能的模糊控制具有更好的控制效果和鲁棒性。

Semi-active control on seismic responses of vibration-insulated urban elevated bridges

Semi-active control via magnet rheologic(MR) dampers for control of the relative displacement between adjacent segments of a seismic isolated continuous girder bridge is investigated,and fuzzy logic control(FLC) is performed by combing offline optimization and online self-tuning.Taking the relative displacement between adjacent segments as the objective function to be minimized,the membership function,the quantification factor and the scaling factor of basic FLC are offline optimized by using a genetic algorithm(GA).The quantification and scaling factors of the optimized FLC are self-tuned online.The semi-active control for a simplified four degrees of freedom system of an isolated multi-span continuous girder bridge is numerically simulated,and the control effects for different control strategies are compared.The results indicate that the control effect of installing MR dampers between superstructure and piers on the relative displacement between adjacent segments of bridge is superior to that of installing MR dampers between adjacent segments.Relative displacement and bearing deformation may be effectively decreased by employing the semi-active control strategy.Comparing with the conventional FLC and the FLC optimized by GA only,the FLC with online self-tuning performance has better control effect and robustness.