建筑物在地震作用下的倒塌是造成地震灾害的主要原因,如何合理评定建筑物的抗倒塌能力是结构抗倒塌设计的前提条件,也是对现有结构进行抗震性能鉴定与加固的基础。该文提出采用结构整体抗震性能系数作为结构整体抗侧向倒塌能力的定量评定指标,以一榀严格按我国规范设计的钢筋混凝土框架结构为例,采用Pushover分析方法对其进行侧向增量倒塌分析,通过结构的失效模式来识别结构的破坏过程,得到了结构超强系数、延性系数、延性折减系数、反应修正系数以及位移放大系数,分析中考虑了不同侧向力分布形式、梁柱线刚度比、柱端弯矩增大系数(COF)对结构抗倒塌能力的影响。研究结果表明:通过结构整体抗震性能系数可以对结构整体抗倒塌能力进行定量评估,可以实现结构延性与承载力的双重控制。
Structural collapse is the main reason of earthquake disaster, and the rational assessment of the lateral incremental collapse resistant ability of a structure is not only a prerequisite for the design, but also is the basis for the identification of seismic performance and for the strengthening of an existing structure. In this paper, the seismic performance factors are used to quantify sidesway collapse resistant capacity of codified designed structures. A structural failure mode is used to identify the process of collapse, the system overstrength factor, the ductility factor, the ductility reduction factor, the response modification coefficient and the deflection amplification factor are all obtained, and the effects of the distribution of lateral loadings, beam-column's linear stiffness ratio and column overdesign factor (COF) are considered in the analysis. It is demonstrated that based on seismic performance factors, we can quantitatively assess the sidesway collapse resistant capacity of the structure, and realize dual control of structural ductility and capacity.