New technique for flexural strengthening of RC columns with NSM FRP bars

Abstract

The effectiveness of fibre reinforced polymer (FRP) jackets for increasing the compression strength, shear strength and ductility of reinforced concrete (RC) columns has been demonstrated in many studies, but the influence of fibre reinforced polymer jacketing on the flexural capacity of columns is minimal. In this paper, a new retrofit method, which utilises near-surface mounted (NSM), fibre reinforced polymer, is developed to improve the flexural capacity of reinforced concrete columns subjected to bending and compression. This technique is based on bonding fibre reinforced polymer bars into grooves cut in the cover of reinforced concrete columns. For this purpose, seven reinforced concrete column specimens were designed, constructed and subjected to constant axial compression and lateral cyclic loading. In addition, the strengthened columns were wrapped with carbon composites to satisfy seismic detailing requirements. The test results show that the proposed strengthening technique is feasible and effective for improving the flexural capacity and energy dissipation capacities of reinforced concrete columns.