Seismic Performance of Asymmetric Buildings

Abstract

Requirements in aesthetics and functionality has resulted in modern buildings to have complex shapes and thus irregularity in the distribution of mass, stiffness and strength in their design. Asymmetry in plan formed because of the eccentricity between Centre of Mass and Centre of Stiffness in buildings and structures can cause undesired rotation and shall result in lateral-torsional coupling modes. This effect can weaken the buildings under extreme
dynamic loads such as Earthquakes, Tsunamis etc. This vulnerability is further affected by the uncertainty in building parameters such as material, geometry and the distribution of asymmetry. Probabilistic analysis techniques such as fragility curves have been found to be an effective index to determine the seismic response of buildings, but not much study has been done on asymmetric buildings. The present study aims at developing the fragility curves
of mass asymmetric RC buildings using non-linear time history analysis and under varying degrees of eccentricity and building height. The investigation proposes advancement over existing damage parameters with which the vulnerability is measured. Metamodel-based non-statistical stochastic analyses have also been done, where input-output relationships were formed which can almost accurately predict the linear and nonlinear response of
buildings with least computational effort.