This work reports on an experimental investigation dealing with the effects of transverse reinforcement, in the form of stirrups, on the behaviour under load of high performances concrete (HPC) beams. The crack patterns and crack widths, the failure modes, the…
This work reports on an experimental investigation dealing with the effects of transverse reinforcement, in the form of stirrups, on the behaviour under load of high performances concrete (HPC) beams. The crack patterns and crack widths, the failure modes, the shear strengths and the ductility of HPC beams containing transverse stirrups were assessed and compared to those in ordinary concrete beams. The test results show that the use of transverse reinforcement in the form of stirrups restrains efficiently the inclined cracking and enhances the aggregate interlocking, known to be weaker in HPC without transverse reinforcement, and thus improves the shear strength of HPC beams. They also improve the contribution of the main longitudinal reinforcement to the shear strength through the dowel action. Finally, the transverse reinforcement improves appreciably the ductility of HPC beams at the ultimate state. In some cases, they changed the failure mode from a brittle shear to a markedly ductile flexure with an increased ultimate carrying capacity. The test results concerning the transverse reinforcement contribution to the shear strength are compared with those predicted by Eurocode 2. The comparison reveals a considerable overestimation of the contribution of the transverse reinforcement to the shear strength of HPC beams by the Eurocode 2. This reduces the safety margin required against shear failure, often catastrophic, and may even lead to unsafe shear design for high performances concrete.