SEISMIC ANALYSIS OF MULTISTOREY BUILDINGS WITH SHEAR WALL

Abstract

The object of the study was to understand the performances of two structural systems (Dual frame systems and Wall systems) is about 20 storey buildings, effect of vertical irregularity on seismic response of buildings and special confinement reinforcement in columns and shear-walls and the influence of boundary element in shear-walls in terms of ductility. The performance of the dual frame system and structural wall system is compared in terms of storey drifts, storey shears and maximum roof displacement of structure. The storey drift of Building A (Dual frame System) is 70% more than Building B (Structural wall System). The storey shear is 5% more in Building B at lower storeys; it is increased to 30 % at top storeys. Displacement ductility of Building Al in X-direction is 4.35 and Y-direction it is 4.92; the displacement ductility of Building A2 in X-direction 4.36 and in Y-direction 4.26. The results of research revel that the structural wall systems gives better performance than the dual frame systems as a high rise buildings, and performance of dual frame system fulfil all seismic demands requirements in case of elastic and inelastic analysis cases. There is very less difference in storey drifts, storey shears between building with or without vertical irregularity. The storey drift difference is about 3% and storey shear difference is about 5%. As per pushover analysis, building with vertical irregularity looks stiffer than building without vertical irregularity. Based on the results of elastic analysis and static pushover analysis it can be concluded that the effect due to vertical irregularity, due to increasing stiffness of one storey does not have significant effect on the seismic behaviour of such buildings. Provisions for special confinement reinforcement in columns of IS-13920 are compared with those of ACI 318. Based on the results presented in this paper, it can be concluded that there is a need to revise the clauses related to confinement of reinforcement for columns and shear walls in IS: 13920 to make them clearer, economical and more user friendly for placement at site. The aim of this study was also to explore possibilities offered by ETABS software packages with user friendly interface to analyze complex buildings. In this case using ETABS complex shapes like C, I, L and simple straight shapes analyzed and designed. A comparison was made between shear-wall with boundary elements and shear-wall without boundary elements. The moment-curvature relationship was drawn for each cross section. Based on the results it is concluded that the shear-wall with boundary element is more economical and ductile than shear-wall without boundary elements.