底层柔性柱隔震结构半主动控制研究

为减小隔震结构底部柔弱层的过大变形,提出了一种底层柔性柱隔震结构半主动控制体系。将结构底层柱设计成柔性柱,在底部填充墙与二层梁之间安装磁流变阻尼器,根据主动控制算法来适时调整阻尼器的阻尼力,对结构实施限位和耗能的半主动控制。建立结构振动模型,通过数值模拟分析该体系的振动特点和减震效果。研究表明,这种结构控制体系能有效减小结构的地震反应,隔震层位移减小50%以上,防止结构因底部位移过大而倒塌。隔震层刚度对减震效果有明显影响,层间刚度比应在隔震层位移、层间位移和加速度之间权衡考虑,并保证底层柱在大震下不发生失稳。在没有半主动控制条件的情况下,在隔震层安装固定阻尼耗能器件进行被动控制,也可减小底层位移30%以上。

STUDY OF ISOLATION STRUCTURES WITH UNDERLYING FLEXIBLE COLUMN BY SEMI-ACTIVE CONTROL

In order to reduce the bottom displacement of isolation structures,this paper proposed a semi-active control system with isolation structures of underlying flexible columns. The underlying columns were designed into flexible columns,then the magnetorheological dampers were installed between bottom filler walls and layer beams. Adjusting the damping force of the dampers in time based on active control algorithm,the semi-active control system can limit the bottom displacement and consume earthquake energy. This paper established the vibration model and analyzed the vibration characteristics and damping effect of this system by the numerical simulation. The conclusions indicate that the system can reduce the structural seismic response effectively,particularly the displacement of isolation layer can be reduced by more than 50%. The control of oversize displacement can prevent the structure collapsing. The layer stiffness ratio can affect the control effect greatly. It should be determined considering the displacement of isolation layer,the layer displacement and the acceleration. meanwhile,should avoid the unstability of the underlying columns in violent earthquake. If there is no semi-active control conditions,passive control with fixed dampers between the isolation layer can reduce over 30% of the bottom displacement.