Influence of axial compression on the shear capacity of transversally rc beams

The present contribution deals with the influence of axial compression on the shear capacity of reinforced concrete (RC) beams. In a previous work (Wahbi et al. 2020, Influence of axial compression on the shear capacity of RC beams without stirrups), an experimental program of 18 RC beams without shear reinforcement subjected to shear under compression was performed. Comparison of the experimental shear resistances with those predicted by Eurocode 2 showed that such a design code may be unconservative in overestimating the beneficial effects of axial compression, but ignores significant favourable effects of negative bending moments on the shear strength of RC beams. As a continuation of the previous work, this paper presents an additional experimental program carried out on 18 RC beams with stirrups. The loading conditions also consisted of a three-point bending-inducing loading with a transverse load on the one hand, an axial compression and a negative bending moment applied at each end of the beams on the other hand. Three values of axial compressive force were studied, and the test beams were also divided into two series with small and large negative bending moments, respectively. During the tests, digital image correlation was used to capture the evolution of cracking on the specimens, allowing to study the influence of loading on the failure cracks. Finally, the experimental shear capacities of these specimens have been compared with the predictions of Eurocode 2 in order to assess their practical validity.