Limit analysis is a computationally efficient tool to assess the resistance and the failure mode of structures but does not provide any information on the displacement capacity, which is one of the concepts which most affects the seismic safety. Therefore, since many researchers did not consider limit analysis as a possible tool for the seismic assessment of structures, its widespread employment has been prevented. In this paper this common belief is questioned and the authors show that limit analysis can be useful in the evaluation of the seismic performance of frame structures. In particular, to overcome the limitation on the possibility to evaluate the displacements of a structure based on a limit analysis approach, an approximated capacity curve is reconstructed. The latter is based on a limit analysis strategy, which takes into account the second order effects, and evaluates the displacement capacity considering a post-peak softening branch and a threshold on the allowed plastic rotations. Then, based on this simplified capacity curve, an equivalent single degree of freedom system is defined in order to assess the seismic performance of frame structures. The proposed simplified strategy is implemented in a dedicated software and the obtained results are validated with well-established approaches based on nonlinear static analyses, showing the reliability and the computational efficiency of this methodology.

中文翻译：

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极限分析评估框架结构抗震性能的新方法

极限分析是一种计算效率很高的工具，可用于评估结构的抗力和破坏模式，但不提供有关位移能力的任何信息，而位移能力是最影响地震安全性的概念之一。因此，由于许多研究人员没有将极限分析作为结构抗震评估的可能工具，因此阻止了其广泛使用。在本文中，这种普遍的观念受到质疑，作者表明极限分析可用于评估框架结构的抗震性能。特别地，为了克服基于极限分析方法评估结构位移的可能性的限制，重建了近似的容量曲线。后者基于极限分析策略，考虑到二阶效应，并考虑峰后软化分支和允许的塑料旋转阈值来评估位移能力。然后，基于此简化的能力曲线，定义了等效的单自由度系统，以评估框架结构的抗震性能。所提出的简化策略在专用软件中实现，并且基于非线性静态分析的成熟方法验证了所获得的结果，显示了该方法的可靠性和计算效率。定义了等效的单自由度系统，以评估框架结构的抗震性能。所提出的简化策略在专用软件中实施，并且基于非线性静态分析的成熟方法验证了所获得的结果，显示了该方法的可靠性和计算效率。定义了等效的单自由度系统，以评估框架结构的抗震性能。所提出的简化策略在专用软件中实施，并且基于非线性静态分析的成熟方法验证了所获得的结果，显示了该方法的可靠性和计算效率。