Deep embedment strengthening of full-scale shear-deficient reinforced concrete beams

The deep embedment (DE) technique is a recently developed shear strengthening method for existing reinforced concrete (RC) structures. The majority of RC beams strengthened using the DE method had effective depths of less than 400 mm. This is unrepresentative of several practical situations where RC girders/beams have significantly higher effective depths. This paper examines the shear behaviour of full-scale unstrengthened as well as strengthened RC T-beams. The beams had an effective depth of about 600 mm, a shear span to effective depth ratio of about 3.0, and were reinforced with internal steel shear reinforcement. The DE shear strengthening system consisted of six 12 mm diameter sand-coated glass fibre reinforced polymer (GFRP) bars in each shear span. The DE GFRP bars enhanced the shear force capacity of the strengthened beam by about 96%. The strengthened beam had a slightly higher cracked stiffness due to the presence of the DE GFRP bars which resisted inclined crack opening and consequently controlled deflection. The main shear crack in the strengthened beam had a steeper inclination. For strengthened beams with light steel shear reinforcement, the results suggest that the total shear force capacity can be calculated as the sums of the concrete, steel, and FRP contributions.