脉冲型地震动作用下隔震结构动力响应的影响参数研究

通过对隔震结构进行非线性动力响应分析,分别研究地震动参数和支座参数对结构地震响应的影响。首先,建立铅芯橡胶支座基础隔震结构的非线性运动方程;然后,以人工合成脉冲型地震动作为输入,运用MATLAB进行编程并求解结构在脉冲型地震动作用下的地震响应;最后,分别研究速度脉冲周期、支座屈服力、屈服后与屈服前的刚度比对隔震支座最大位移和上部结构层间位移的影响。研究结果表明,脉冲周期对结构地震响应影响很大,在进行隔震设计时应使结构自振周期远离脉冲周期;支座刚度比对结构地震响应影响较大,在进行支座选型时应重点关注;支座屈服力对支座位移的影响显著,屈服力越大,支座位移越小。

Parametric Study on Dynamic Response of Base-isolated Structure Subjected to Pulse-like Ground Motions

The use of base-isolation technology to resist earthquake damage has attracted much attention since its appearance. Many researchers at home and abroad have conducted studies focused on base-isolated structures under seismic ground motions. Near-fault pulse-like ground motions comprise a velocity or displacement pulse component and other components. Some research results showed that near-fault pulse-like ground motions can cause severe damage to structures. Seismic responses of base-isolated structures under near-fault ground motions have attracted much attention in recent years. Synthetic ground motions were used as input, then the influence of ground motion parameters and isolation-bearing parameters on base-isolated structural seismic responses were analyzed on the basis of nonlinear dynamic time-history analysis. First, a nonlinear motion equation of a base-isolated structure was established. Second, the structural nonlinear dynamic responses were solved under synthetic pulse-like ground motions by using MATLAB. And last, the effects of the velocity pulse period, the yield force of the isolation bearing, and the stiffness ratio of the isolation bearing on dynamic response of the isolation layer and superstructure were studied. Research results show that the effect of the velocity pulse period on the structural dynamic response was great, and the structural natural period should be distant from the pulse period. The influence of the stiffness ratio on structural response was significant, and it should be taken seriously when choosing isolation bearings. The yield force of the isolation bearing had a great influence on bearing displacement, and when the yield force became greater, the bearing displacement became smaller.