平面钢框架瞬时冲击去柱抗连续性倒塌试验研究  

Tests for progressive collapse of planar steel frames under a column sudden removal

作　　者：李国强[1,2] 李六连 陆勇[3] LI Guo-qiang LI Liu-lian LU Yong(College of Civil Engineering, Tongji University, Shanghai 200092, China State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University, Shanghai 200092, China Institute for Infrastructure and Environment, School of Engineering, The University of Edinburgh, Edinburgh EH9 3JL, UK)

机构地区：[1]同济大学土木工程学院,上海200092 [2]同济大学土木工程防灾国家重点实验室,上海200092 [3]爱丁堡大学工程学院

出　　处：《振动与冲击》2017年第11期48-56,64,共10页Journal of Vibration and Shock

基　　金：国家自然科学基金重大国际合作研究项目(51120185001)

摘　　要：采用冲击去柱法对两个平面钢框架进行抗连续性倒塌试验研究,重点关注去柱后框架结构的动力反应、倒塌机制以及梁柱受力方式的转变。试验结果表明,在整个倒塌过程中,框架结构经历了弹性受力阶段-弹塑性受力阶段-悬链线形成阶段;框架梁经历了弯曲机制抵抗外荷载到悬链线机制抵抗外荷载的转变;相邻框架柱的弯曲刚度越大,对去柱后形成的双跨梁的约束越强,梁的悬链线效应就越大。对于强梁弱柱型框架结构,由于其框架柱较弱,瞬时去柱后,易发生柱失稳型连续性倒塌。采用ABAQUS6.11对抗倒塌试验进行模拟,模拟结果与试验结果吻合较好。结合试验结果,采用有限元模型分析了平面钢框架倒塌时的动力放大系数和最终倒塌模态。This paper presents an experimental investigation into the dynamic behavior of planer steel frames under a sudden column removal scenario. Two planner frames were tested, and the sudden removal of a middle column was realized by a specially designed mechanism which was disengaged through a hammer impact. Based on the experimental results, the dynamic response, collapse modes, and the change of load transfer paths of the steel frames following the removal of the middle column are studied. The beams above the removed middle column suffered the largest deformation, and their response went through 3 distinctive stages, namely an elastic stage, an elastic-plastic stage and a catenary stage; meanwhile these beams experienced a transition of the resistance mechanisms from bending to catenary action in transferring the loads. A steel frame designed in accordance with the strong beam-weak column approach can be prone to a progressive collapse due to buckling of the columns adjacent to the removed column. To simulate the experimental processes, a finite element model was developed with refined shell elements using ABAQUS. The results from the numerical models are in good agreement with those from experiments. Using the validated finite element model, the collapse modes of the planar steel frames are further analyzed. The dynamic amplification factor in the progressive collapse is also discussed based on both the experimental and numerical results.

关 键 词：平面钢框架 连续性倒塌 悬链线机制 倒塌模式 

分 类 号：TU391[建筑科学—结构工程]