AN ASSESSMENT OF POUNDING EFFECT IN R.C. FRAMED STRUCTURES

Abstract

Pounding preventive gaps are usually not provided between buildings standing adjoining to each other in cities having high land prices or which are unplanned. Such buildings may collide to sustain major structural damages including reduction in overall stiffness of the structure which in extreme cases may lead to complete collapse under seismic activity. Various strengthening measures which can be adopted is proposed along with the optimum position of installation near the beam-column location. This paper discusses about the installation of Buckling resistant bracings (BRB), steel bracings and shear wall which proved to be beneficial in mitigating the pounding phenomena and greatly reduces the lateral deflection. Here two models are considered having different structural dynamics property each is analysed firstly with bare frame and then after properly strengthening with bracings and shear wall. Five spectral matched and matched ground motions are also provided for analysis. The method used for analysis after placing bracings or shear wall includes majorly non-linear pushover analysis to check the possible hinges and capacity of structure and then non-linear time history analysis is performed to know the actual behaviour of the buildings after strengthening. The analysis is repeated by shifting the bracings and shear wall at various locations in both the buildings one after another. The result was checked by comparing the sum of lateral displacements of both the buildings at concerned storey level before and after the strengthening is done. From the result various conclusion are drawn to get the optimum locations of Buckling resistant bracingss, steel bracing and the shear wall. It is found that all the locations of bracings were capable of mitigating pounding effect and the one which has least value is taken as the optimum location.