应用MRF-04K阻尼器的大跨连续刚构桥地震反应的半主动控制

应用最近设计制作的MRF-0 4K型磁流变(MR)阻尼器对大跨连续刚构桥的地震反应实施半主动控制。首先建立了多支承不同步地震激励下大跨连续刚构桥的运动方程,并基于瞬时最优控制算法建立了大跨连续刚构桥地震反应控制的计算方法,数值仿真分析了某四跨预应力混凝土连续刚构桥在不同控制策略下地震反应的控制效果,结果表明当在该连续刚构桥的两端各安装5 0个MRF-0 4K阻尼器,中墩墩顶水平位移降低7 0.4%,中跨跨中竖向位移降低7 7.7%,边跨跨中竖向位移降低6 6.0%。最后得出结论:应用MRF-0 4K阻尼器能使多支承不同步地震激励下大跨连续刚构桥的地震反应得到有效的控制,主动控制效果明显地高于被动控制效果,且半主动控制能取得理想的控制效果,即使地震发生时半主动控制系统失效,同样可以取得理想的控制效果,从而为MRF-0 4K阻尼器的工程应用提供了理论依据。

SEMI-ACTIVE CONTROL ON THE SEISMIC RESPONSES OF LONG-SPAN CONTINUOUS RIGID-FRAMED BRIDGES USING MRF-04K DAMPER

A semi-active control on the seismic responses of the long-span continuous rigid-framed bridges is performed using a recently designed and manufactured magnetorheological (MR) damper,MRF-04K.The equations of motion are established for the long-span continuous rigid-framed bridges under multi-support asynchronous seismic excitations,and the calculation method for the control of the seismic responses of the long-span continuous rigid-framed bridges is proposed,based on the Instantaneous Optimal Control algorithm. The control effect on the seismic responses of a four-span prestressed concrete continuous rigid-framed bridge is numerically simulated under different control strategies, and the results show that when 50 MRF-04K dampers are installed at the two ends of the continuous rigid-framed bridge, the peak lateral displacement at the top of the middle biers is reduced by 70.4%, the peak wertical displacement at the mid-point of the middle spans is reduced by 77.7% and the peak vertical displacement at the mid-point of the side spans is reduced by 66.0%. The conclusions are given that the seismic responses of long-span continuous rigid-framed bridges under multi-support asynchronous seismic excitations can be effectively controlled using the MRF-04K dampers, the effect of active control is considerably higher than that of passive control, and the ideal control effect can be achieved by using semi-active control even though the semi-active control system is inactive when the earthquake occurs. This serves as a theoretical basis for engineering applications of the MRF-04K dampers.