【摘要】 基于性能的抗震设计需要揭示准确有效的地震动参数以满足结构易损性研究的要求。选择开展结构观测的6层钢结构作为分析实例,建立结构有限元模型。以Northridge地震中结构反应记录作为输入开展结构模态和动力反应分析。利用地震记录识别结构的自振特性和位移反应,将识别结果与分析结果进行对比,直至模型分析结果与识别结果吻合,完成有限元模型的标定。选择20条地震动开展结构增量动力分析,将基于PGA和Sa(T1)的顶层位移角分布曲线与Pushover分析曲线进行对比。分析表明Sa(T1)较PGA更适合开展该结构易损性研究。建立Sa(T1)和层间位移角的关系曲线,确定达到某一层间位移角水平的地震动数量,并以此作为计算概率密度函数的依据,构造出Probit概率密度模型,得到该结构达到不同破坏状态的易损性曲线。分析表明钢结构具有良好的抗震性能,适用于地震高风险区的建设工程。更多还原

【Abstract】 The performance-based seismic design needs to reveal accurate and effective ground motion parameters to meet the requirements of structural vulnerability study. Firstly, we selected a 6-story steel building to build a finite element model, and took the structure response recordings in Northridge earthquake as the input to analyze the structure model and dynamic response. Secondly, we identified the natural vibration characteristics and displacement responses of structures using seismic records, and compared identification results with the analysis results until they tally with each other and completed the calibration of the finite element model. Finally, we selected twenty ground motions for incremental dynamic analysis, and compared the top displacement angular distribution curve based on PGA and Sa（T₁） with Pushover analysis curve. It’s shown that Sa（T₁） demonstrates a better applicability than PGA for fragility analysis in this building. The relationship curve between Sa（T₁） and interlayer displacement angle is established to determine the number of ground motions reaching a certain level of interlayer displacement angle. Based on this, we could calculate the probability density function and construct the Probit probability density model to the fragility curves of the structure under different damage states. The comprehensive analysis shows that the steel structure has good seismic performance and is suitable for construction projects in high-risk areas of earthquakes.更多还原