Shear strengthening of RC beams using near-surface mounted carbon fibre-reinforced polymers

Abstract

ABSTRACTThis paper summarises the results of experimental work on reinforced concrete beams strengthened in shear using near-surface mounted carbon fibre-reinforced polymers (NSM-CFRP). Fourteen beams (150 × 200 × 1200 mm) in dimension, with insufficient shear reinforcement, were tested under four-point bending. The effects of side concrete cover depth, NSM-CFRP strip inclination angle and NSM-CFRP strip length on the behaviour of RC beams were studied. Six of the beams were cast with three different side concrete cover depths, 20, 30 and 40 mm, and strengthened in shear by NSM-CFRP, with inclination angles of 0° and 45°. Other beams with a side concrete cover depth of 30 mm were strengthened in shear by NSM-CFRP with different strip lengths, measured in terms of beam depth (full, 2/3, and 1/3) and inclinations of 0° and 45°. The results show that the concrete side cover depth enhances the behaviour of NSM-CFRP-strengthened beams. Beams with inclined NSM-CFRP strips experienced higher ultimate strengths than those with vertical NSM-CFRP. It was found that ultimate strength increases with longer strip length.