上部结构与基础隔震层偏心对结构地震响应的影响

随着基础隔震技术的发展,我国在高烈度地区广泛开展基础隔震技术的工程应用必将成为一种趋势,但由于建筑功能和建筑造型的丰富多彩,结构的质量中心和刚度中心也趋于分布不均匀,以三层的钢框架结构为分析模型,利用结构分析软件Sap2000对上部结构质量中心和隔震层质量中心、刚度中心分布不均匀的三种方案进行单向水平地震作用下的非线性时程分析,分析结果表明:上部结构质量中心与隔震层质量中心存在偏心距对结构的扭转效应以及地震响应有较大的影响,减小上部结构的偏心距对调整结构的水平地震响应的影响成效最为显著;对于隔震层而言,隔震层的刚度中心偏心距较质量中心偏心距对上部结构的影响更大,有效控制隔震层刚度中心的偏心距在隔震设计中会更加有效。

Influence of Eccentricity of the Upper Structure and BaseIsolation Layer on the Structural Seismic Response

With the development of base isolation technology, the engineering application of the technology in high-intensity areas in China is expected to become a trend. However, because of the rich and intriguing architectural functions and modeling, the mass center and stiffness center of the structure tend to be unevenly distributed. Taking a three-story steel frame structure as the analytical model, the nonlinear time-history analysis was carried out under one-directional horizontal seismic action using SAP2000, and three schemes were designed:the uneven distribution of the superstructure mass center, uneven distribution of the isolation layer mass center, and uneven distribution of the isolation layer stiffness center. The analysis results showed that the eccentricity of the mass center of the superstructure and isolation layer has a great influence on the torsion effect and seismic response of the structure, and reducing the eccentricity of the superstructure has the most significant effect on the horizontal seismic response of the structure. The eccentricity of the stiffness center of the isolation layer has a greater influence on the superstructure compared with the eccentricity of the mass center; therefore, it is more effective to control the eccentricity of the isolation layer stiffness center in isolation design.