The IUP Journal of Structural Engineering
Seismic Analysis of Reinforced Concrete Buildings with Coupled Irregularities

Article Details
Pub. Date : July, 2023
Product Name : The IUP Journal of Structural Engineering
Product Type : Article
Product Code : IJSE010723
Author Name : Jahanvi Suthar and Sharadkumar Purohit
Availability : YES
Subject/Domain : Science and Technology
Download Format : PDF Format
No. of Pages : 17



Reinforced Concrete (RC) buildings with irregularities, plan and vertical, are susceptible to seismic damage. Such buildings are constructed due to functional, space and aesthetic considerations. Most practical irregular RC buildings have coupled irregularities: plan or vertical or mixed. The seismic behavior of coupled irregular RC buildings is an active area of research. In the present paper, five RC building models with coupled reentrant corners and vertical geometric irregularities are developed along with the regular RC building model. L-shaped and stepped-shaped reentrant corners type plan irregularity is coupled with vertical geometric irregularity by changing plan dimension at each floor level of RC building models. Building models are analyzed for seismic forces following the Indian seismic design code. Seismic parameters-peak base shear, peak displacement, peak interstory drift ratio, modal analysis, normalized base shear and normalized overturning moment-are extracted. It is found that peak displacement and peak interstory drift ratio of coupled irregular building models shows a substantial increase vis-a-vis regular building models. Normalized base shear and normalized overturning moment increase for all coupled irregular building models, except building model BM-3, as compared to the regular building model.


Buildings with symmetrical geometry comprising uniformly distributed mass and stiffness in both plan and elevation are considered as regular buildings. However, such buildings are being constructed due to functional and aesthetic requirements and thus become irregular buildings. There are other reasons like space constraints, economy, local authority and regulations responsible for constructing irregular buildings. There are varieties of irregularity possessed by building in plan and elevation. As per IS: 1893 (Part-1): 2016, plan irregularity includes torsional irregularity, reentrant corners, floor slabs having excessive cutouts or openings, out-of-plane offsets in vertical elements and nonparallel lateral force systems, while vertical irregularity includes stiffness irregularity (soft story), mass irregularity, vertical


Reentrant corner, Setback building, Flexible diaphragm, Seismic analysis