采用静-动力转换方法的钢管混凝土框架受火倒塌非线性分析
Progressive Collapse Nonlinear Analysis on Composite Frames with CFST Columns Based on Static-dynamic Analytic Conversion Procedure in Fires
作者：王景玄(兰州理工大学 土木工程学院, 甘肃 兰州 730050;西部土木工程防灾减灾教育部工程研究中心, 甘肃 兰州 730050)；王文达(兰州理工大学 土木工程学院, 甘肃 兰州 730050;西部土木工程防灾减灾教育部工程研究中心, 甘肃 兰州 730050)；李华伟(兰州理工大学 土木工程学院, 甘肃 兰州 730050)
Author：WANG Jingxuan(School of Civil Eng., Lanzhou Univ. of Technol., Lanzhou 730050, China;Western Center of Disaster Mitigation in Civil Eng. of Ministry of Education, Lanzhou 730050, China)；WANG Wenda(School of Civil Eng., Lanzhou Univ. of Technol., Lanzhou 730050, China;Western Center of Disaster Mitigation in Civil Eng. of Ministry of Education, Lanzhou 730050, China)；LI Huawei(School of Civil Eng., Lanzhou Univ. of Technol., Lanzhou 730050, China)
收稿日期：2016-09-02 年卷（期）页码：2017,49(4):53-60
期刊名称：工程科学与技术
Journal Name：Advanced Engineering Sciences
关键字：钢管混凝土;连续倒塌;火灾响应;纤维模型;静-动力转换法;非线性分析
Key words：concrete filled steel tube;progressive collapse;fire response;fiber beam element model;a static-dynamic analytic conversion procedure;nonlinear analysis
基金项目：国家自然科学基金资助项目（51268038）；兰州理工大学“红柳杰出人才培养计划”资助项目（JQ201305）
中文摘要
火灾引起结构倒塌不同于其他瞬时倒塌破坏（地震、冲击或者爆炸），倒塌全过程为准静态平衡和动态相结合的复杂过程。为研究局部火灾引起的钢管混凝土框架结构倒塌破坏机理和动力响应，基于ABAQUS预定场和重启动功能，采用静-动力转换分析方法进行某9层钢管混凝土空间框架结构体系的受火连续性倒塌非线性分析，研究该结构第6层角部开间受火场景下的倒塌破坏模态，分析梁、柱构件受火失效引起的空间框架全过程倒塌机理及整体结构产生动力效应的影响规律。框架梁柱构件均采用纤维梁单元，钢筋混凝土楼板采用分层壳单元，钢材和混凝土材性采用自定义开发的单轴本构材料模型。分析结果表明，静-动力转换方法可以较好地模拟结构受火倒塌全过程，节省计算时间，同时能够反映结构的动力特性。由空间框架倒塌全过程示意可知，角柱失效后触发结构发生局部连续倒塌破坏，倒塌临界时间为253 min（4.2 h），结构整体的耐火时间远大于单个构件的耐火要求。火灾引起结构的局部倒塌全过程分为5个阶段：受火初期膨胀阶段、局部屈曲阶段、短暂平衡阶段、卸载阶段和局部倒塌破坏阶段；前4个阶段为长持时的准静态分析，第5阶段为非线性动力问题。此外，受火区域竖向构件失效后，其卸载传力路径遵循就近原则。
英文摘要
Fire induced collapse failure mode is different from other instantaneous collapse,such as that induced by earthquake,impacting or exploding.The whole collapse is a combination of complex processes including quasi-static equilibrium and dynamic process.In order to research the nonlinear dynamic response of progressive collapse analysis on the composite frame with concrete filled steel tubular (CFST) columns and RC slabs due to local fire.A static-dynamic analytic conversion procedure has been developed based on the restart and predefined-field function in the finite element code ABAQUS.This paper presents a FE model of 9-story composite spatial frame to investigate the mechanism of progressive collapse when 6th corner floor catches fire.The composite frame members of columns and steel beams used nonlinear fiber beam elements,and RC slabs used layered shell elements.The user-defined uniaxial constitutive material models of core concrete and steel were incorporated in subprogram UMAT.The results showed that the analytic procedure switch between static and dynamic analysis was effective to investigate the progressive collapse of composite frame subjected to fire,and it could shorten the calculation time and show the dynamic characteristics of progressive collapse.Local progressive collapse was observed in the composite frame when the corner column was destroyed.Collapse critical fire resistance time was 253 min (4.2 h),greater than the individual component.The displacement of top column included five stages when it was subjected to fire,including inflation deformation in early heating stage,localized failure of heated columns,transient equilibrium phase,unloading phase and the localized collapse phase.The first four stages were long quasi-static analysis and the fifth stage was a nonlinear dynamic problem.The redistribution of internal forces during unloading followed the "shortest path principle" in general.
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