Seismic fragility analysis can accurately estimate seismic performance of a structure, to propose a method to study on the seismic fragility of space grid structure, the full-load field time-history analysis, parameter sensitivity analysis and seismic fragility analysis were carried out. The results show that space grid structure has a ductile damage with obvious signs. The responses of this kind of structure are more sensitive to steel yield strength, floor loads and ground motion records, which can be considered as random factors in subsequent analysis. The seismic damage index and damage grading standard, which are applicable to orthogonal pyramid space grid, were proposed based on the seismic response of whole process. According to the seismic fragility analysis, the probability of ensuring intactness at PGA=0.40g is 95%, while 79% at PGA=0.62g. The orthogonal pyramid space grid has a good seismic performance, which can largely ensure the seismic safety.%地震易损性分析能准确评估结构抗震性能,为了提出一种网架结构地震易损性的研究方法,对正放四角锥平板网架结构开展了全荷载域时程分析研究其失效机理、参数敏感性分析研究各参数的影响程度、地震易损性分析评价其抗震性能.分析结果表明:网架结构破坏属于延性破坏,具有明显预兆;结构响应对钢材屈服强度、楼面荷载以及地震动记录的敏感性较大,后续分析中应视为随机性因素考虑;提出了适用于正放四角锥平板网架楼盖的地震损伤程度指标及震害等级划分标准,并给出针对该结构的地震易损性分析方法及步骤;分析发现结构在峰值加速度为0.40g(8度罕遇)时保证完好的概率仍有95%,即使出现0.62g(9度罕遇)强烈地震时,结构保证完好的概率仍能达到79%.正放四角锥平板网架楼盖具有较好的抗震性能,很大程度保证了结构的地震安全.
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