TORSIONAL ANALYSIS OF BUILDINGS

Abstract

The need for providing resistance to torsion in the structures has been recognized for only two decades back. A rational basis has been discussed for determining the torsional effects in buildings arising basically from two sources — eccentricity in mass and stiffness distribution (i.e. usual codal provision) and wave propogation effects in earthquake motions that give a torsional input to the ground as well as torsional motion in the earth itself during earthquake. Previously torsional response of the structu±es due to rocking and torsional components of ground motions was neglected. - Due to gradual development in the subject rocking and torsional components of ground motions are beginning to attract the attention of engineering and resear:oh communities and now it has become evident that these motions contribute to the overall response of the structures particularly high rise and unsymmetric structures. A resume of various National Codes including the Inter-national Code of Practice and recommendations of the App lied Technology Council regarding the provision of torsion has been made herein. An attempt has been made in this thesis to highlight the contribution of the torsional component of ground motion end to compare the design parameters with codal provisions.