Experimental Study And Numerical Analysis On Shear Capacity Of RC Beams With Diagonal Cracks

RC beams are widely used in engineering practice, and the shear capacity of RC beams is the focus for people. The diagonal crack is one of the most popular deterioration in civil infrastructure, and it is difficult to avoid the appearance of diagonal cracks. Diagonal cracks make RC beams broke suddenly in the form of shear failure, and reduce the shear capacity of beams. They are directly related to the safe use and the service life of RC beams. But it is lack of a quick way to estimate the shear capacity of RC beams with diagonal cracks for existing criterions and literatures. As a result, it is important to study the shear behavior of reinforced concrete beams, and to find a simple and rapid method to estimate the shear capacity of RC beams.In this paper, experimental study and numerical analysis on shear capacity of RC beams with diagonal cracks was studied. And the main work and research conclusions ware as follows.First, based on cyclic loading experiment of six beams in the two groups, the relationship among the average web stress, initial diagonal crack width and shear capacity of RC beams was studied in this paper. Experimental result shows that the impact of cyclic loading for RC beams can be characterized by the width of diagonal crack, and the decline of the shear strength of the RC beams due to the decline of the shear strength of concrete caused by diagonal cracks. According to the experimental phenomena, the shear compression failure mechanism of beam and existing criterions, using diagonal crack width as a variable, a formula for shear capacity after cyclic loading was derived for engineering use in this paper.Second, in order to further investigate the shear failure mechanism, with experimental data, numerical simulation of shear pressure was made for the RC beams in this paper, by characterizing the diagonal crack width caused by cyclic loading as the concrete crack face shear transfer coefficient. It found that the numerical results consistent with the experimental phenomena and results in this paper. Finally, comparing with the numerical simulation results and the experimental results, the formula for RC Beams with diagonal cracks in this paper is safe and practical for engineering use.