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研究砌体加层隔震结构体系下部结构出现损伤后的抗震性能,重点关注隔震层上部、下部结构频率比变化对下部结构响应的影响。采用随机振动理论推导加层隔震体系与加层非隔震体系下部结构加速度响应均方值比,给出了下部结构加速度响应均方值比随频率比的变化规律,分析表明对于加层隔震结构,出现损伤前隔震效果明显,但随着下部结构刚度的不断退化,加层隔震体系下部结构的地震响应会超过加层非隔震结构体系。对加层隔震和加层非隔震结构进行了振动台试验研究,对比试验模型损伤前后各楼层加速度反应,分析其损伤前后减震效果的变化,试验结果表明,初始加层隔震模型地震响应明显小于加层非隔震模型,但随着加层隔震结构下部砌体的不断损伤,加层隔震体系的减震效果逐渐降低,下部结构甚至出现了加速度反应被放大的不利现象,试验现象和数据与理论分析结果吻合良好。在加层隔震结构的分析和设计中必须考虑下部结构出现损伤后对结构的不利影响。
The seismic performance of the lower structure of the masonry plus story isolation structure system is studied. The effect of the frequency ratio change of the upper and lower structure of the isolation layer on the response of the lower structure is mainly concerned. The stochastic vibration theory is used to derive the mean square value of the acceleration response of the substructure of the layered seismic isolation system plus the non-isolated seismic isolation system. The variation law of the square root of the acceleration response of the substructure with the frequency ratio is given. However, with the continuous degradation of the substructure stiffness, the seismic response of the substructure with the additional seismic isolation system will exceed that of the non-isolated seismic isolation system. Shaking table test was carried out on the laminated and non-isolated structures. The acceleration response of each floor before and after the damage was compared and the change of the damping effect before and after the damage was analyzed. The experimental results show that the initial seismicity of the superimposed isolation model The response is obviously smaller than that of the non-isolated basement model. However, with the continuous damage of the masonry at the lower part of the laminated seismic isolation structure, the damping effect of the laminated seismic isolation system is gradually reduced, and even the lower part of the structure appears an unfavorable phenomenon that the acceleration response is amplified. The experimental phenomena and the data are in good agreement with the theoretical analysis. In the analysis and design of the additional seismic isolation structure, the adverse effect on the structure after the damage of the lower structure must be considered.