ABSTRACT

The computational complexity and high computational costs are the main obstacles to estimate the seismic demand and capacity of non-linear structural systems and assess their seismic performance under strong earthquake events. On the other hand, the current response modification factors for seismic design of structures are mainly based on a single performance target, and therefore, cannot be directly used in modern performance-based design procedures. In this study, a low computational cost method is adopted for seismic performance assessment of steel moment-resisting frames and development of multi-level modification factors by using the newly-developed Endurance-Time method. The efficiency of the proposed method is demonstrated for 3, 5, and 7-storey frame examples. It is shown that compared to conventional methods using time-history and pushover analysis techniques, the proposed approach can significantly (up to 80%) reduce the computational costs. The results indicate that push-over analyses may lead to inaccurate results, while a good agreement is generally observed between the seismic demands predicted by Endurance-Time and Time-History methods (less than 10% error). The results of Endurance-Time method are then used to develop multi-level response modification factors for steel moment-resisting frames by taking into account the effects of earthquake intensity and the target performance level. It is shown that Endurance-Time method can accurately estimate the response modification factors and the corresponding earthquake intensity levels with significantly less computational cost compared to the conventional methods using incremental dynamic analysis. The proposed multi-level response modification factors should prove useful in performance-based seismic design of steel moment-resisting frames.

摘要

计算复杂性和高计算成本是估计非线性结构系统的抗震需求和能力以及评估其在强地震事件下的抗震性能的主要障碍。另一方面，目前结构抗震设计的响应修正因子主要基于单一的性能目标，因此不能直接用于现代基于性能的设计程序。在这项研究中，采用低计算成本的方法对钢抗弯框架进行抗震性能评估，并使用新开发的 Endurance-Time 方法开发多级修改因子。对于 3、5 和 7 层框架示例，证明了所提出方法的效率。结果表明，与使用时程分析和 Pushover 分析技术的传统方法相比，所提出的方法可以显着（高达 80%）降低计算成本。结果表明，push-over 分析可能导致结果不准确，而通过 Endurance-Time 和 Time-History 方法预测的地震需求之间通常观察到良好的一致性（误差小于 10%）。然后利用Endurance-Time方法的结果，在考虑地震烈度和目标性能水平的影响下，开发钢抗弯框架的多级响应修正因子。结果表明，与使用增量动力分析的传统方法相比，Endurance-Time 方法可以准确地估计响应修正因子和相应的地震烈度等级，且计算成本显着降低。所提出的多级响应修正因子应该证明在钢抗弯框架的基于性能的抗震设计中是有用的。