Comparative Study on Lateral Load Response of Steel Frame Structure with Different Bracing System

Abstract

Multistory buildings are mostly affected by earthquake force in seismic prone area. The major concern in the design of multistory building is mainly to have enough lateral stability to resist lateral forces and to control the lateral drift of the buildings. The Steel bracing is viable for resisting lateral forces. To know the importance of different bracing systems in the multistory steel frame structure a linear static analysis of different storey buildings are considered such as 6, 9, and 12 storey, of five by seven bays steel building. Modal response spectrum analysis for seismic zone IV was carried out based on ESEN 1998-1:2014 using ETABS v9.6.0 software. There are two plan layout, these are regular and L-shape. The bracings that studied were diagonal brace, inverted V (chevron) brace, V-brace, K-brace and X-brace, and the performance of each frame has been carried out. The arrangements used; corner braced and all frames are analyzed without bracing and with all types of bracing. A total of 36 different models were analyzed and compared. Among the listed types of bracing X bracing and inverted V bracing shows higher performance in lateral load resistance. In plan regular structure X bracing shows better performance by increasing base shear and base overturning moment capacity, and inverted V bracing more efficient by minimizing the lateral displacement. For irregular structure inverted V bracing shows a more resistance in all cases, which is better in reduction of lateral displacement and increase in base shear and base overturning moment. As per the comparisons made, braced frame have showed a reduction of top storey displacement of 55.3% in the X direction and 61.6% in the Y direction. The base shear resistance of the building also increased by 136% and 308% in the X and Y direction respectively. Similarly the base overturning moment resistance of the building increased by 134% and 308% in the X and Y direction respectively.