近断层地震作用下隔震结构基底碰撞响应分析及倾覆倒塌模拟*
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杜永峰1,2,王小虎1，朱翔1(1 兰州理工大学防震减灾研究所,兰州 730050； 2 西部土木工程防灾减灾教育部工程研究中心，兰州 730050)［摘要］近断层脉冲型地震作用下，建筑的隔震层会产生较大的侧移，与周边基坑挡墙可能发生碰撞。采用非线性弹簧来模拟基坑挡墙，考虑上部结构的弹塑性变形。利用基于非线性弹簧的碰撞模型，分析了近场、远场地震作用下隔震结构的碰撞响应，探讨了隔震结构与周边基坑的预留间距对隔震结构碰撞的影响。并通过二次开发，采用生死单元法，模拟了碰撞导致隔震结构的倾覆倒塌。基于增量动力分析(IDA)的分析结果表明：近场地震作用下隔震结构更容易发生碰撞，对隔震结构的倾覆效应更具相关性，碰撞导致隔震支座产生受拉破坏继而发生倾覆倒塌。［关键词］近断层地震；隔震结构；碰撞响应；倒塌模拟；增量动力分析中图分类号：TU352.12 文献标识码：A 文章编号：1002-848X(2013)02-0056-04Overturning collapse simulation of isolation structure under near-fault seismic motion considering potential poundingDu Yongfeng1,2, Wang Xiaohu1, Zhu Xiang1(1 Institute of Earthquake Protection and Disaster Mitigation, Lanzhou University of Technology, Lanzhou 730050, China; 2 Western Center for Disaster Mitigation in Civil Engineering of Ministry of Education, Lanzhou 730050, China)Abstract: The isolation story will have a greater deformation, potential pounding may occur at the isolation level between the building and its surrounding retaining walls under the near-fault pulse-type seismic motion. Non-linear springs were employed to simulate the impact of the boundary, and elastic-plastic deformation of the upper structure was also considered. The pounding response of the isolation structure under near-fault and far-fault seismic and the impacts of the pounding under different tectonic space were studied by the collision model based on non-linear springs. Through "birth-death” element defined in the user’s subroutine, collapse leaded by pounding was simulated. The Incremental Dynamic Analysis(IDA) result shows that structures under near-fault seismic are more likely to crash compared with far-fault seismic, and it is more relevant with overturning of isolation structure. Simulation results show that pounding lead to isolation bearing damage and subsequent overturning collapsed.Keywords: near-fault earthquake; seismic isolated structure; pounding response; collapse simulation; IDA*国家自然科学基金（50978130）参考文献［1］ MALHOTRA P K. Dynamics of seismic impacts in base-isolated buildings［J］. Earthquake Engineering & Structural Dynamics, 1997, 26(8): 797-813.［2］ TSAI H C. Dynamic analysis of base-isolated shear beams bumping against stops［J］. Earthquake Engineering & Structural Dynamics, 1997, 26(5): 515-528.［3］ 叶昆, 李黎. LRB基础隔震结构在近断层脉冲型地震作用下的动力响应研究［J］. 工程抗震与加固改造,2009, 31(2): 32-39.［4］ 叶昆, 李黎. 改进的Kelvin碰撞分析模型［J］. 工程力学, 2009, 26(SⅡ): 245-248.［5］ 叶献国, 谢一可, 李康宁. 基础隔震结构在侧向碰撞下的地震反应分析［J］. 地震工程与工程振动, 2008,28(4): 161-167.［6］ 符蓉，叶昆，李黎. LRB基础隔震结构在近断层脉冲型地震作用下的碰撞响应［J］.工程力学,2010,27(SⅡ): 298-302.［7］ 樊剑, 刘铁, 魏俊杰. 近断层地震下摩擦型隔震结构与限位装置碰撞反应及防护措施研究［J］. 土木工程学报, 2007, 40(5):10-16.［8］ 叶昆, 李黎. 近断层脉冲地震作用下偏心基础隔震结构的地震反应研究［J］. 工程力学,2009,26(7):163-169.［9］ 杜永峰,李慧. 双向地震激励下隔震结构抗倾覆特性的数值分析［J］. 计算机辅助工程, 2011, 20(1):42-46.
