A STUDY OF TORSIONAL EFFECT ON MULTI-STORIED BUILDING WITH PLAN-IRRGULARITY.

Abstract

In this paper seismic performance of multistory building is check with asymmetrical plan. At re-entrant corner maximum damage is occur during earthquake. A G+20 and G +22 building having plan Asymmetry is modeled in finite element analysis using STADD-Pro v8i.Accenditial torsional load is applied with reference to 1893(part-1)-2002.In this paper we provide architectural relief and providing shear wall at re-entrant corner in the buildings.A building should posses four main attributes, namely simple and regular configuration, and adequate lateral strength, stiffness and ductility to perform well in earthquake. Buildings having simple regular geometry and uniformly distributed mass and stiffness in plan as well as in elevation, suffer much less damage than buildings with irregular configurations. But due to architectural consideration we have to construct buildings with irregular according is1893 clause 7.1 irregular define in two ways plan irregularities and vertical irregularity. Torsion is caused in building during earthquake due to various reasons, mainly due to non-symmetric mass distribution and stiffness. Torsion is generated in asymmetrical building when the distance between storey's center of rigidity and storey's center of mass is greater than 20% of the width of the structure in either major plan dimension. In torsion irregularity, inertia force acts through the center of mass while the resistive force acts through the center of rigidity as shown in fig 1.