Effects of the Transverse Reinforcement on the Shear Behaviour of High Strength Concrete Beams

Abstract

This paper presents the results of an experimental investigation dealing with the effects of transverse reinforcement on the crack patterns, the ultimate carrying capacity and the ductility of beams made of high strength concrete and normal strength concrete for comparison purposes. The test results are analyzed and compared with the shear provisions in the four major universal codes (ACI-318; BS-8110; Eurocode 2; BAEL 99). Twenty six reinforced concrete beams with and without transverse reinforcement were constructed using different shear-span to depth ratios (a/d = 1.5, 2.0 and 3.0) and different compressive strengths of concrete (44 MPa, 65 MPa and 86 MPa). The test results indicate that the presence of transverse reinforcement had controlled efficiently the crack width by enhancing the aggregate interlocking on the crack surface, increased moderately the shear strengths of the beams by factors ranging from 1.14 to 1.86, and increased appreciably the ductility of beams at the ultimate state. It should be noted, however, that the beams failed at shear strength contributions of transverse reinforcement ( Vs) considerably lower than the values predicted by the models used in the four major universal codes. This translates that the existing universal design codes may not be rationally safe against shear design of high strength concrete beams containing transverse reinforcement.