对跨海桥梁震浪响应的半主动控制策略

Semi-active control strategy for reduce the earthquakeinduced wave responses of sea-crossing bridges

建立了桥梁震浪响应的磁流变液阻尼器(MRD)控制方程,首先将MRD在下一时刻的出力预测值作为半主动控制系统的限界约束,并构造适合MRD的剪切型最优(CO)半主动控制目标函数;然后基于精细积分法把MRD半主动控制策略等效为一列在附加限界约束内使目标函数取最小值的方程组;最后利用可靠区理论求解方程组得到MRD的半主动控制力.以一座三跨跨海公路连续梁桥为工程背景,分别对其在未控制、TRIO半主动控制、CO半主动控制和线性二次型最优(LQR)主动控制下的各评价指标进行了数值计算.结果表明:提出的TRIO半主动控制策略在降低桥梁震浪响应方面比传统的CO半主动控制的效果显著;TRIO半主动控制的MRD控制力峰值逼近LQR主动控制的,对外界能源的利用率比LQR策略的要高得多.

The equation which can be used for control the earthquake-induced wave responses of sea- crossing bridge by using the magnetorheological fluids damper （MRD） was established. Firstly, the control forces predicted values of MRD at the next time step were obtained and they were considered as limit constraints for the semi-active control system, and the clipped optimal （CO） semi-active ob- jective function for MRD was constructed. Secondly, the semi-active control strategy for MRD was equivalent to equations which let the objective function to minimum in the range of limit constraints based the precise integration method. Finally, the semi-active control forces of MRD were obtained by solving above equations based the trust region theory. Taking the three-spans sea-crossing continuous girder highway bridge as the engineering background, the various evaluation criteria of the sea-cross- ing bridge with the non-control, TRIO semi-active control, CO semi-active control and linear quadrat- ic regulator （LQR） active control were computed by using numerical method, respectively. The re- sults show that the earthquake-induced wave responses reduction effect of TRIO semi-active control strategy proposed by this paper are obvious advantage over the traditional CO semi-active control. The MRD peak control forces of TRIO semi-active control are approximate to those of LQR active control, and the utilization ratio of external energy of TRIO strategy are much higher than those of LQR strat- egy.