COMPARISON OF EXPERIMENTAL SEISMIC RESPONSE OF CONVENTIONAL AND BASE ISOLATED BUILDINGS WITH ANALYSIS

Abstract

Base isolation is regarded as a promising solution of earthquake resistant design, which results in significantly low floor accelerations, and inters storey drifts. This ensures the safety of structural as well as non structural elements, thereby keeping the building operational even after a severe earthquake. The effectiveness of a base isolation system is governed by the bilinear characteristics offered by the isolators. The present work attempts to study the effectiveness of base isolation over conventional seismic construction, using a case study of identical conventional and isolated building constructed for experimental purposes in Guwahati, a seismically active region in India. The comparison of analytical results with the records for two actually recorded low intensity earthquakes is done. A further analysis of the test buildings for the recorded earthquake scaled to a moderate and high intensity is also carried out. An algorithm using simplified shear building procedure for a time history analysis of MDOF systems with localised bilinear behaviour has been developed, and a MATLAB program, "MDOFbilin" has been written to execute the algorithm. The program is used to perform a comparative analysis of bare frame and infilled frame models of the test buildings subjected to actually recorded earthquakes, and the analytical results have been compared with the instrumental records. A comparison of the analysis of base isolated building using the MATLAB program with a general 3D analysis in SAP is presented for the Koyna earthquake. It is observed that the program uses a simplified method, requires a less execution time and still gives reliable results