基于增量动力分析的钢框架-混凝土剪力墙结构地震易损性

易损性是结构本身的一个特性,是结构在不同地震强度指标作用下,达到特定失效状态或性能水平的可能性。建立钢框架-混凝土剪力墙结构的非线性分析模型,采用增量动力分析方法对结构进行地震易损性研究,提出地震需求参数与地震动强度指标之间的关系,绘制易损性曲线;并结合地震倒塌储备系数对结构的抗震能力进行定量分析。结果表明:结构在立即使用状态时,易损性曲线斜率较大,曲线较陡,说明结构在震后不需经过修理仍可使用,随着谱加速度的增大,结构的超越概率急剧上升。结构在防止倒塌和整体失稳状态时,曲线走势趋于平缓,说明结构进入弹塑性状态后,耗能能力显著增强,结构的抗震倒塌能力可以满足规范要求。倒塌储备系数与结构的倒塌能力呈正相关变化趋势。研究结果为结构的抗震及倒塌能力评估提供参考。

Seismic fragility analysis of steel frame-concrete shear wall structure based on the incremental dynamic analysis method

Seismic fragility, as a feature of the structure, is the probability to reach a specific failure state or performance level under earthquake with different intensity. The nonlinear analysis model of steel frame-concrete shear wall structure is established, and the seismic vulnerability of that is studied with the using of the incremental dynamic analysis method. The fragility curves were drawn by the analysis of the relationships between seismic demand parameters and seismic intensity index. Meanwhile, the seismic capacity of the structure was quantitatively analyzed, combining the seismic collapse reserve coefficient. It is shown that the vulnerability curve is steeper and the slope of that is larger at the stage of IO, which indicated that the structure can still work without repairing after subjecting earthquake. As the increase of spectral acceleration, the exceedance probability of structure increases sharply. The trend of curve tends to be gentle at the stage of CP and GI. The elastic-plastic state of structure reaches, the energy dissipation capacity of that is improved significantly and the plastic deformation of that develops rapidly until collapse happened. The collapse reserve coefficient is positively correlated with the collapse ability of the structure. Base on the method of IDA, the seismic fragility analysis can provide an effective scientific basis for evaluating the seismic collapse resistance of the structure.