基于能量的模态pushover分析方法

Energy-based modal pushover analysis method

提出了一种基于能量的模态pushover分析方法,解决了高阶模态能力曲线失稳的问题。该方法利用基于结构变形吸收能量的等效位移,计算结构在地震作用下的非线性总体变形,替代模态pushover中基于顶点位移的变形解法,采用基于能量原理的等效单自由度体系,结合等强度谱计算目标位移,以目标位移对应的能量指标求出相应的结构性态反应,采用SRSS方法组合得到结构的最大反应。以9层钢框架结构为例对所提出方法进行了验证,结果表明:该方法可以考虑高阶效应,不会出现能力谱折返的失效情况,而且与时程分析法相比,该方法计算效率高且具有较好的精度。

In order to solve the instability issue that arise in some high modal pushover analysis （MFA）, an energy-based modal pushover analysis method is proposed. Rather than adopting the calculation formula of deformation based on the roof displacement in modal pushover analysis, this paper employs the equivalent displacement based on energy in determination of the nonlinear responses of the entire building. The target displacement was established by the energy-based equivalent single degree of freedom system and constant-strength displacement response spectra. The structural performance was evaluated with the target displacement based on energy, and the maximum deformation was calculated with SRSS combination procedure. The method was verified with a 9-story steel building. The results show that the method takes into account the higher-mode effects and avoids the instability returning phenomenon. And the method possesses high computing efficiency and favorable precision compared with the nonlinear time history analysis.