框架结构抗地震倒塌能力的研究——汶川地震极震区几个框架结构震害案例分析

Seismic collapse resistance of RC frame structures——Case studies on seismic damages of several RC frame structures under extreme ground motion in Wenchuan Earthquake

介绍了汶川地震中极震区几组相同场地条件下倒塌与未倒塌框架结构的震害案例,并分别采用弹塑性时程分析方法、推覆分析方法和基于IDA的结构倒塌储备系数分析方法,对其中2个典型框架结构的抗地震倒塌能力进行了分析研究。在此基础上,结合国外关于结构抗地震倒塌计算方法及其相关研究,分析了影响结构抗倒塌能力的主要影响因素和评价指标。研究结果表明,保证结构的整体承载力储备和变形能力,增加结构的冗余度和整体性,采取有效措施使结构形成合理的屈服机制,充分利用填充墙使框架结构形成双重抗震防线,可显著提高框架结构的抗倒塌能力。最后提出了结构抗地震倒塌需进一步研究的问题。

The seismic damage of several groups of RC frames in the hardest-hit zone of the Great Wenchuan Earthquake is introduced. In each group, some frames collapsed while others survived, despite that they had similar site condition. The collapse resistance of two typical frames in earthquake is analyzed with elastic-plastic time-history analysis, pushover analysis and collapse margin ratio（CMR） analysis which is based on incremental dynamic analysis （IDA）. The corresponding collapse resistance research and calculation methods in foreign countries are introduced. The main influencing factors and the evaluation indices that control the structural collapse resistance, as well as the global redundancy and integrity, are discussed. Based on this study, the following methods are identified to be effective in improving the collapse resistance of frames ： （1） guarantee the global loading resistance capacity and lateral deformation capacity; （2）increase the redundancy and integrity; （3）achieve rational yield mechanism with proposed engineering method ; （4） buildup dual-system for frame structures with infill walls. Finally, the problems that may need further research on structural collapse are proposed.