Study on the Effects of P-Delta Analysis on RC Structures

Abstract

This study investigates the influence of P-Delta effects on the structural behaviour of L-shaped reinforced concrete multistory buildings. Irregular high-rise structures are becoming common due to growing urbanization. It makes second-order analysis important for perfect design. The research executes three building models of 15, 20, and 25 stories using ETABS. These have linear static, response spectrum, and corresponding P-Delta analyses. Important structural parameters like lateral displacement, story drift, and story shear are compared and analysed. The outputs show that inclusion of P-Delta effects increases displacement, drift, and shear forces, with the impact becoming more pronounced as building height increases. The 25-story model exhibits the highest sensitivity to second-order effects. The study shows that neglecting P-Delta effects can lead to unsafe and unconservative designs, emphasising the necessity of incorporating second-order analysis in medium and high-rise irregular structures, especially in seismic regions. Additionally, geometric irregularity in L-shaped buildings amplifies torsional behaviour and stress concentration.