Vulnerability of asymmetric multi-storey buildings in the context of performance-based seismic design

Abstract

Many existing buildings with reinforced concrete structure have, in reality, irregular configurations especially in plan. This category of edifices cannot be avoided due to the functional and architectural requirements. Under strong earthquake trembling, they experience inelastic behaviour which causes torsional effect, one of the most important factors influencing the seismic damage of RC structures during an earthquake. The main intent of this study is to investigate the 3 D seismic demands of RC asymmetric-plan structures by employing Displacement-based Adaptive Pushover methodology. The torsional effect on the structures is considered by varying eccentricity subjected to Pushover Analysis and Non-Linear Time History Analysis, setting up equivalent single degree of freedom system. For this purpose, the seismic behaviour of three asymmetric-plan buildings was studied by considering uncertainties associated with the randomness of the seismic action using accelerograms of real earthquakes compatible with target design spectra. From capacity curves, the damage states and corresponding fragility curves can be obtained. Based on Fibre-element modelling, the analysis of the models is done using OpenSees under Eurocode 8 compliant real record sets. In the damage functions, the results obtained from static and dynamic analyses are compared and discussed with suggestions for future research and seismic provisions.