RC空间框架结构竖向倒塌全过程试验研究与理论分析

EXPERIMENTAL AND THEORETICAL ANALYSES ON ENTIRE COURSE OF VERTICAL PROGRESSIVE COLLAPSE OF SPATIAL RC FRAME STRUCTURES

采用抽柱法对一双层双向RC空间框架结构进行了拟静力倒塌试验,分别研究了框架结构底层边中柱失效后,剩余结构的竖向倒塌过程、倒塌机制和倒塌细节。试验结果表明:RC空间框架结构竖向倒塌分为外推阶段(拱作用阶段)、内收阶段(悬链线作用阶段)和倒塌阶段三个阶段;现浇楼板推迟甚至避免了梁铰出现,具体与现浇楼板对梁的约束大小有关;RC空间框架结构具有良好的抗连续倒塌性能,但应特别注意现浇楼板对结构抗连续倒塌性能的影响。在试验研究基础上,分析了RC空间框架结构竖向倒塌机制的转化过程,提出了最大侧向变形和临界塌落位移的计算模型和求解方法,建立了结构损伤指数模型。

A quasi-static test is carried out to experimentally study the vertical progressive collapse of a two-storey by two-bay spatial RC frame structure. The progressive collapse mechanism and collapse details of the residual structure due to a side column loss are simulated by unloading the jack, replacing the failure column. The experimental results indicate that: the whole vertical-collapse damaged-process of RC spatial frame structures can be divided into three stages, including an extrapolation stage(arch action stage), an adduction stage(catenaries action stage) and a collapse stage; the appearance of plastic hinges, which are relative to the binding effects of slabs on beams, can be put off or even be skipped; RC spatial frame structure has a fine anti-collapse performance, but the influence of cast-in-situ slabs on anti-collapse performance of a structure should be considered seriously; the theoretical method for maximum lateral displacement and the mathematical model and the method for the critical displacement of the slumping column are raised in the combination of an experimental research and a theoretical analysis; what is more, the structure damage indictor model was proposed.