The trends of irregular building construction have rapidly increased due to aesthetic and limited availability of land. Past studies have shown that the structures with configuration irregularity are damaged under strong ground motion. Structural irregularities are important factors which decrease the seismic performance of the structures. Buildings having structural irregularities result in the uneven distribution of the story drift, excessive torsion, etc. according to the irregularity type and may fail during an earthquake. One such form of irregularity is the presence of re-entrant corners and torsional irregularity that causes stress concentration due to sudden changes in stiffness and torsion amplification in buildings. In this context, the present study evaluates the effect of plan configuration irregularity when subjected to the varying angle of the input response spectrum. For this, one regular and six different L-shaped RC building frames were modeled for numerical analysis. The analysis was done through an equivalent static lateral force method and response spectrum analysis (dynamic analysis). The structural responses were measured in terms of story displacement, inter-story drift ratio, torsional irregularity ratio, torsional diaphragm rotation, normalized base shear force, and overturning moment. The results indicate that buildings with plan configuration irregularity are more sensitive to the varying angle of the input response spectrum as compared to the symmetrical building model. The significant increase in seismic response demand was observed when the finite element models were subjected to a 135-degree angle as compared to the zero-degree angle of seismic incidence. In addition, the study shows that the fundamental time period of structure based on standard code shows a lower value as compared to a finite element approach. It is concluded that to account for the irregularities present within the buildings, current code provisions are insufficient and should be amended.

由于美学和土地有限，不规则建筑的趋势迅速增加。过去的研究表明，具有不规则形状的结构在强烈的地面运动下会受到破坏。结构不规则是降低结构抗震性能的重要因素。具有不规则结构的建筑物会根据不规则类型导致层错分布不均匀，过度扭转等，并且可能在地震中失效。这种不规则的一种形式是凹角和扭转不规则的存在，它们由于刚度的突然变化和建筑物中的扭转放大而引起应力集中。在这种情况下，本研究评估了在输入响应谱的变化角度下平面配置不规则的影响。为此，对一个常规和六个不同的L形RC建筑框架进行了建模以进行数值分析。通过等效的静态侧向力方法和响应谱分析（动态分析）进行分析。根据层位移，层间漂移率，扭转不规则率，扭转膜片旋转，规范化基础剪力和倾覆力矩来测量结构响应。结果表明，与对称建筑模型相比，具有平面配置不规则性的建筑物对输入响应谱的变化角度更加敏感。与零度角地震入射角相比，当有限元模型承受135度角时，观察到地震响应需求的显着增加。此外，研究表明，与有限元方法相比，基于标准代码的结构的基本时间段显示出较低的值。结论是，考虑到建筑物内存在的不规则性，当前的规范规定不足，应予以修订。