Fragility Analysis of RC Frame Building with Plan Irregularities

Abstract

The damage to the buildings during recent earthquakes has demonstrated the need for seismic evaluation which is used to predict the probability of damage to the building. The aim of this work is to derive the fragility curve at the limit state. The present study evaluates the seismic responses of buildings with plan irregularities. To obtain an accurate and reliable estimate of the probability of exceeding the chosen damage parameter, traditional methods require the development of a large number of computational models that represent the Plan irregularities in the particular building type, as well as earthquake time history analyses. Various methods like the Non-linear static method (Pushover method), linear dynamic method (Linear Time History method) are carried out to identify the probability distributions of 3 selected damage states for seismic hazard estimation for G+5 story Reinforced Concrete (RC) Building is carried out by developing Fragility Curves. Fragility Curves are developed for maximum story displacement, maximum inter-story drift, and spectral displacement of RC buildings through Linear Time History and pushover analysis, respectively. The probability of exceeding each damage level in each scaled earthquake intensities of applied 28 ground motions is determined by both methods. Fragility Curves of RC buildings developed using the guidelines of FEMA-440 is carried out to study the improvement of guidelines later over the former and obtain the performance point for RC buildings using commercial software. The fragility curves of the target building and revised model building were derived by the statistics analysis considering the lognormal accumulative distribution function. The RC building has a high likelihood of exceeding immediate occupancy for low PGA values, but a low probability of exceeding for life safety and collapse prevention.