连续体系桥梁的主动及混合控制抗震研究

Study of Seismic Resistance of Active and Hybrid Control Methods of Continuous System Bridges

为研究连续梁桥及刚构桥的主动及混合控制抗震效果,以某4×50m单箱预应力混凝土桥为例,采用基于支座初始刚度的LQG主动控制法进行抗震研究。采用MATLAB编程,建立空间梁单元有限元模型,通过震动控制仿真平台NLAHC1.0对有限元模型施加LQG主动控制,加入主动施力器及传感器,采用模态缩减技术及Kalman滤波器建立控制模型,对连续梁桥和刚构桥的墩底横桥向弯矩及支座的剪力～位移曲线进行分析,并提出了一种新的改进控制法。结果表明：主动控制抗震方法能显著减小刚构桥的墩底弯矩,而混合控制抗震方法不能有效减小连续梁桥的墩底弯矩;考虑支座非线性引起的结构刚度矩阵变化,改进控制法对混合控制连续梁桥的减震效果明显。

To check the seismic resistance effect of the active and hybrid control methods of the continuous girder bridge and rigid-frame bridge,a 4×50-m span prestressed concrete single-box girder bridge was taken as an example and the seismic resistance effect was studied,using the linear-quadratic-Gaussian（LQG）active control method based on the initial rigidity of the bearings.The MATLAB program was used to set up the spatial beam finite element model and by means of the vibration control simulation platform NLAHC1.0,the LQG active control was exercised to the model and the active load appliers and sensors were introduced.Further by means of the modal reduction technique and the Kalman filters,the control model was set up,the transverse moment in the pier footings and the shear～displacement curves of the bearings of the continuous girder bridge and rigid-frame bridge were analyzed and a new improved control method was hence put forward.The results demonstrate that the seismic resistance of the active control method can significantly reduce the moment in the pier footing of the rigid-frame bridge while the seismic resistance of the hybrid control method can not effectively reduce the moment in the pier footing of the continuous girder bridge.In consideration of the structural rigidity matrix changes due to the nonlinearity of the bearings,the improved control method has significant effect on the seismic mitigation of the continuous girder bridge using the hybrid control method.