One way for decreasing the effect of pounding is to set the separation gap between two adjacent buildings. On the one hand, earthquakes in earthquake-prone zones often occur as a chain of successive earth movements in the form of foreshock, mainshock and aftershock. On the other hand, the existence of soft story in the lowest story of the structure is the most common type of irregularity in lateral stiffness. This paper investigates the effect of seismic sequences to estimate the separation gap at the highest collision level of two adjacent structures. For this purpose, 335 adjacent combinations of regular and irregular steel moment-resisting frames are evaluated which have a soft story on the first story. Separation gap demand is calculated using dynamic analysis of nonlinear time history under a set of seismic sequences which are a combination of the mainshock and aftershock. Results of the total of analysis done show the seismic sequence effects are significant and should be considered in the process of determining the normal separation gap (here after, NSG). Finally, based on the done studies, an empirical relationship is presented to estimate the seismic sequence effects on separation gap of two regular and irregular adjacent structures.

中文翻译：

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主震-余震对规则与不规则相邻结构与软层分离间隙估计的影响

减少冲击效应的一种方法是设置两个相邻建筑物之间的间距。一方面，地震多发区的地震通常以前震、主震和余震形式的一系列连续的地球运动发生。另一方面，在结构的最低层存在软层是侧向刚度中最常见的不规则类型。本文研究了地震序列对估计两个相邻结构最高碰撞水平处的分离间隙的影响。为此，对 335 个相邻的规则和不规则钢抗弯框架组合进行了评估，这些框架在第一层上具有软层。分离间隙需求是在一组主震和余震组合的地震序列下使用非线性时程的动态分析来计算的。完成的全部分析结果表明，地震序列效应是显着的，应在确定正常分离间隙（以下称为 NSG）的过程中加以考虑。最后，在已有研究的基础上，提出了一种经验关系式来估计地震序列对两个规则和不规则相邻结构的分离间隙的影响。