COMPARISON OF BRACINGS AND SHEAR WALLS AS SEISMIC STRENGTHENING METHODS TO BUILDINGS WITH PLAN IRREGULARITIES

Divyashree M, Bhavyashree B N, Gopi Siddappa

Abstract: Failure of reinforced concrete structures during the past earthquakes has taught us the importance of evaluation of the seismic capacity of the existing buildings. Presence of irregularities is considered as a major deficiency in the seismic behavior of structures. One such forms of irregularity is the presence of re-entrant corners which causes stress concentration due to sudden changes in stiffness and torsion in the buildings due to plan asymmetry. Strengthening the notch of the re-entrant cornered buildings is very essential to ensure a good seismic performance of such buildings. Introduction of bracings and stiff shear walls are the popular methods of strengthening the buildings against their poor seismic performance. This paper aims at comparing the efficiency of these two methods of strengthening of irregular buildings. For this purpose, eight storey buildings are modeled and analyzed by response spectrum and pushover analysis methods using ETABS software. Analysis is carried out for different configurations of bracings and shear walls as strengthening elements with varying stiffness. Results of the analysis confirm the reduction in roof top displacement with the increase in the stiffness of the strengthening elements. Further, for a similar performance level the efficiency and economy of both strengthening methods are compared using a cost comparison analysis. Results of the analysis have showed that shear walls prove to be more economical compared to bracings for a given performance level

Keywords: Pushover Analysis, Re-entrant corners, Response Spectrum, Storey Drifts

DOI: https://doi.org/10.15623/ijret.2014.0318032