Study on the Response of Strengthening Strategies for Masonry-Infilled Open Ground Storey Framed Building

Aojoy Kumar Shuvo; Ashadul Islam

Abstract

The strengthening of reinforced concrete (RC) frame buildings with masonry-infill wall and with open ground storey is a very timely and significant topic because of the poor performance against seismic action. The absence of infill walls in the ground storey makes the ground storey less stiff and weaker than the all upper story’s which results in a poor performance against lateral loads. Soft storey mechanism prevails in these cases and causes premature failure. The objective of this paper is to oversee the response of different strengthening systems applied in ground storey of the building to improve the seismic behavior based on numerical analyses. The strengthening options are chosen and provided in such a way that the options will not block the free space in the ground storey level which is kept open to serve different purposes. In addition, the study highlights the building performance by obtaining the capacity of different options and represents the variation of time period with the change of stiffness. The strengthening options investigated were design columns of ground storey for higher load, fixing diagonal bracing at the exterior sides, providing lateral buttresses and installing shear wall on exterior four corners. To find out the effective strengthening option without create any obstacle to the service for which the ground storey is kept open, the results from analyses of strengthened buildings will be compared. Keywords: Reinforced concrete frame, Infill masonry, Strengthening options, Seismic effects, Time period.