Application of Buckling restrained braces as lateral strengthening method for on-slopping ground reinforced concrete frame structures under severe earthquake loads

Abstract Buckling restrained braces (BRB) have been proven to be one of the critical horizontal loads resisting structural elements due to their energy dissipation characteristics. Through numerical computational methods using finite element software ETABS, seismic characteristics of- slopping round reinforced concrete frames with different slopes were studied and buckling restrained braces ‘strengthening schemes against their irregularity were proposed. Response spectrum analysis has been used to study the characteristics of typical on-sloping ground frame structures located in regions with seismic intensity eight by using Chinese code for seismic design of building structures GB 2011-2010. It has been found that as the slope increases, the deflection increases, and the period of vibration decreases. It has also been determined that when the slope is only in one direction, the discrepancy between X and Y direction responses will increase as the angle of inclination increases; lastly, it has been found that this type of frame structure will suffer from stiffness irregularity with the severity that increases as the angle of inclination increases. Recent literature has also determined and confirmed that structures on the sloping ground will suffer uneven distribution of internal forces due to the constraints of the columns on the upper side of the slope. To correct all these characteristics, buckling restrained braces were proposed and compared with ordinary steel braces using nonlinear time history analysis. Our results demonstrate that BRB can handle safety issues associated with slopping ground-reinforced concrete frame structures.