Nonlinear time history analysis (NTHA) is widely considered to be the most accurate and robust method of seismic analysis and, when performed with force analogy method (FAM), can result in significant reduction in computational time, as compared to the conventional displacement‐based finite element (FE) solution technique. Taking this advantage of efficient FAM, this paper investigates the effects of location (along building height) and intensity (150–225%) of single‐floor mass irregularity on seismic response of mid‐rise moment‐resisting steel frames. Three building heights (6, 8, and 10 storeys) have been considered, and the analysis results are presented in the form of floor displacements, storey drift ratio, and plastic energy dissipation. Based on the analysis, it has been observed that critical location (for the maximum seismic response) of mass‐irregular floor corresponds to the level that exhibited the maximum seismic response (i.e., storey drift ratio) in the reference mass‐regular frame. Further, criticality of the irregular frame to seismic excitation has been found to decrease when mass‐irregular floor moves towards the top of the building. The criticality of the irregular frame has been found to increase with the increase in mass‐irregular intensity. Collapse of the irregular frame has been seen to initial first near the storey level where mass‐irregular floor is located.

中文翻译：

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用力类比方法进行非线性时程分析的质量不规则性对抗弯钢框架地震反应的影响

非线性时程分析（NTHA）被广泛认为是地震分析中最准确，最可靠的方法，与传统的基于位移的方法相比，当使用力类比方法（FAM）进行分析时，可大大减少计算时间有限元（FE）解决方案技术。利用有效的FAM的优势，本文研究了单层质量不规则性的位置（沿建筑物高度）和强度（150-225％）对中层抗弯钢框架地震响应的影响。考虑了三个建筑物高度（6、8和10层），分析结果以地板位移，层间漂移率和塑性能耗散的形式给出。根据分析，已经观察到，质量不规则地板的关键位置（对于最大地震响应）对应于在参考质量规则框架中展现出最大地震响应（即，层间漂移比）的水平。此外，已经发现，当质量不规则的地板移向建筑物顶部时，不规则框架对地震激励的临界度降低。已经发现，不规则框架的临界度随不规则质量的增加而增加。不规则框架的塌陷首先在质量不规则地板所在的楼层附近开始出现。人们发现，当不规则质量的地板移向建筑物顶部时，不规则框架对地震激励的临界性降低。已经发现，不规则框架的临界度随不规则质量的增加而增加。不规则框架的塌陷首先在质量不规则地板所在的楼层附近开始出现。人们发现，当不规则质量的地板移向建筑物顶部时，不规则框架对地震激励的临界性降低。已经发现，不规则框架的临界度随不规则质量的增加而增加。不规则框架的塌陷首先在质量不规则地板所在的楼层附近开始出现。