Effect of Plan Irregularity on Seismic Performance of the Building

Abstract

Symmetry in the plan is an important feature in building configuration. Vertical irregularity and plan irregularity are commonly noticeable in most of the newly constructed buildings in Bangladesh. Ground motion caused by seismic forces may influence the performance of irregular shaped buildings although they have same plan area. Due to change in building shape, its stiffness and moment of inertia may also be altered which has a great impact on building performance during earthquake. It is very much needed to identify the performance of irregular structures in both plan and elevation against natural disaster (earthquake). In this study, five buildings configurations namely square-formed, L-formed, H-formed, T-formed, and U-formed have been analyzed by response spectrum method through ETABS and their seismic performance have been studied. From the investigation, it has been observed that storey drift, top storey displacement and fundamental time period have been increased rapidly in different shaped buildings compared to regular building. Torsional irregularity is also found in irregular buildings. So, regular building is more preferable in seismic areas.