Seismic Analysis of Re entrant Corner Dominant Plan Irregular RC Buildings

Abstract

Buildings with simple and regular configurations are expected to behave relatively well to seismic events as compared to irregular buildings due to uniform lateral stiffness and strength distribution. However, the construction of buildings with irregular configurations becomes inevitable due to various reasons like effective land utilization, local construction bylaws, air and and light requirements, rapid urbanization, functional requirements and aesthetics. Building irregularities are broadly classified as; plan irregularity and vertical irregularity by most countries seismic codes, including the Indian seismic code, IS 1893 (Part-1): 2016. These irregularities are further classified based on the distribution of geometrical properties in the plan and structural properties in the elevation of the buildings. Buildings with various types of plan and vertical irregularities were found to suffer varied degrees of damages during past earthquakes and incurred capital losses. Many important buildings like; schools, hospitals, emergency fire buildings, and communication towers have been built with various types of irregularities to cater to functional needs. Residential and commercial complexes also have been observed to possess some forms of irregularities. Therefore, understanding the seismic behaviour of such types of buildings becomes important and associated seismic codal provisions shall be assessed from time to time. Out of many types of irregularities, few types of irregularities are commonly practised, one such irregularity is plan irregularity with re-entrant corners. Building with plan layouts of C-, L-, T- and PLUS-shapes possess re-entrant type plan irregularity. While re-entrant type irregularity measured by its building projection ratio (A/L ratio) is restricted to a prescribed value by various seismic design codes, a detailed study on the seismic behaviour of such buildings to ascertain this prescribed value is a research gap. The present research work aims to study the seismic behaviour of re-entrant cor