层间隔震偏心结构双向地震耦合响应研究

Coupling Seismic Response of Inter-story Isolated Eccentric Structures under a Bi-directional Earthquake

摘要:

建立双向地震作用下层间隔震双向偏心结构侧扭耦联分析模型；考虑上部结构及下部结构的弹塑性模型，隔震支座采用双向耦合非线性Bouc-wen模型模拟；分析偏心参数对层间隔震双向偏心结构的影响规律；评价双向地震作用下我国抗震规范给出的扭转影响系数静力预测值的准确性。结果表明，双向地震作用下设置中间柔性隔震层可以减小上、下部结构扭转的耦连效应；下部结构存在双向偏心会对隔震层和下部结构扭转反应带来不利影响；LRB耦合效应对层间隔震地震响应影响较小；当下部结构偏心率较大时现行规范计算扭转系数偏于不安全。

Abstract:

This paper studied the torsional effect of inter-story isolated bi-directional eccentric structures subjected to bi-directional earthquakes. A torsion-lateral coupling analysis model of an inter-story isolated bi-directional eccentric structure under bi-directional earthquakes is presented. Nonlinear properties of both superstructure and substructure were considered. Biaxial force-deformation behavior of the lead rubber bearings (LRB) was simulated by the Bouc-wen model. The influence of eccentric parameters on the inter-story isolated structure was investigated by Matlab software. Numerical simulation was conducted to verify the accuracy of the torsion coefficient formula provided by the Chinese Code of Seismic Design of Buildings (GB 50011-2010). Results showed that the mid-isolation layer significantly reduced the coupling torsion effect of superstructure and substructure under a bi-directional earthquake. The bi-directional eccentric of substructure had an adverse effect on torsion responses. Results obtained from the Chinese seismic code were unsafe when the eccentric ratio of the substructure was too high.