Performance Based Seismic Design of Buildings

Abstract

A performance-based design is aimed at controlling the structural damage based on precise estimations of proper response parameters. Performance-based seismic design explicitly evaluates how a building is likely to perform; given the potential hazard it is likely to experience, considering uncertainties inherent in the quantification of potential hazard and uncertainties in assessment of the actual building response. It is an iterative process that begins with the selection of performance objectives, followed by the development of a preliminary design, an assessment as to whether or not the design meets the performance objectives, and finally redesign and reassessment, if required, until the desired performance level is achieved. In this present study two R.C buildings, one symmetrical and one unsymmetrical in plan (designed according to IS 456:2000) are analysed using Pushover Analysis and redesigning by changing the main reinforcement of various frame elements and again analyzing. The pushover analysis has been carried out using SAP2000, a product of Computers and Structures International. A total of 24 cases for a particular four storey building located in Zone-IV have been analyzed, changing reinforcement of different structural elements, i.e. Beams and Columns, in different combinations as well as at different storey levels. The results of analysis are compared in terms of base shear, storey drift, spectral acceleration, spectral displacement and storey displacements. The best possible combination of reinforcement that is economical, effective and whose damage is limited to Grade 2 (slight structural damage, moderate nonstructural damage) in order to enable Immediate Occupancy is determined and is termed as Performance Based Design. The effect of providing shear walls, on the performance of RC framed building, is also studied using pushover analysis.