不同设防烈度RC框架结构的地震倒塌风险统计与分析  

Statistics and analysis on risk of earthquake collapse of RC frame structures with different fortification intensities

作　　者：罗开海[1] 保海娥[1] 左琼[1] LUO Kaihai;BAO Haie;ZUO Qiong(China Academy of Building Research,Beijing 100013,China)

机构地区：[1]中国建筑科学研究院,北京100013

出　　处：《建筑结构学报》2021年第11期137-144,共8页Journal of Building Structures

基　　金：住房和城乡建设部专题项目(FZYJ(2015)KZ-7);中国建筑科学研究院标准规范项目(20150122336230031);山东省高校土木结构防灾减灾协同创新中心项目(XTZ201906)。

摘　　要：为开展基于一致倒塌风险的抗震设计方法研究,以不同设防烈度下6层RC框架结构模型设计结果为例,采用动力弹塑性时程分析和概率统计的方法对GB 50011《建筑抗震设计规范》约定罕遇地震以及50年超越概率2%地震作用下建筑倒塌概率进行分析,并对建筑倒塌概率的影响因素进行研究。结果表明:结构的最大弹塑性层间位移角服从正态分布;按层间位移角的累积概率进行风险评估,在规范约定罕遇地震下,6度和8度(0.30g)设防RC框架结构的抗倒塌性能有保证,7度(0.1g)、7度(0.15g)和8度设防时倒塌风险显著偏高;在50年超越概率2%地震下作用,8度(0.30g)和9度设防RC框架结构的抗倒塌性能基本有保证,6度、7度(0.1g)、7度(0.15g)和8度设防时倒塌风险显著偏高;结构倒塌风险与预期地震作用下层间位移角平均值具有明显的相关性,严格控制预期罕遇地震下的平均最大层间位移角是确保抗倒塌性能的重要手段;对于中低烈度设防的RC框架结构,规范GB 50011约定罕遇地震峰值加速度明显偏低、结构构件抗震等级低、轴压比限值高、框架柱截面小、结构初始刚度和屈服承载能力偏小等是地震倒塌风险偏高的主要原因。In order to carry out the study of uniform-risk-based seismic design method, taking the design results of the 6-story RC frame structures with different intensity as examples, the probability of building collapse under the rare earthquake specified by GB 50011 and the earthquake with the 2% probability of exceedance in 50 years, were analyzed by means of dynamic history analysis and probability statistics, and the influence factors of the probability of building collapse were studied in depth. The results show that: the maximum elastic-plastic drifts of the structure obey normal distribution;according to the cumulative probability of inter-story drift that taken as the collapse risk, under the rare earthquake specified by code, the anti-collapse performances of RC frame structures with 6 degree and 8 degree(0.30g) are guaranteed, but the risks of collapse of RC frame structures with 7 degree(0.1g), 7 degree(0.15g) and 8 degree are significantly higher;under the earthquake with the 2% probability of exceedance in 50 years, the anti-collapse performances of RC frame structures with 8 degree(0.30g) and 9 degree are basically guaranteed, but the risks of collapse of RC frame structure with 6 degree, 7 degree(0.1g), 7 degree(0.15g) or 8 degree are significantly higher;the risk of structural collapse is obviously related to the average value of the maximum drift under the expected earthquake, and strictly limiting the average drift is an important means to ensure anti-collapse performance;for the RC frame structures with medium or low fortification intensity, the significantly lower peak acceleration of rare earthquakes specified by Code, the lower seismic grade of structural components, the higher axial compression ratio limit, the smaller cross-section of frame column, the smaller initial stiffness, the smaller yield carrying capacity and so on, are the main reasons for the higher risk of earthquake collapse.

关 键 词：RC框架结构 设防烈度 地震倒塌风险 倒塌概率 

分 类 号：TU352.11[建筑科学—结构工程]