Experimental investigations of failure modes of reinforced concrete beams without web reinforcement

•Experimental investigations of damage of RC beams without shear reinforcement.•Statistical analysis of different failure modes occurring for the beams with the same shear span-depth ratio.•Comprehensive analysis of damage scenarios of RC beams without shear reinforcement was discussed. This paper reported an experimental investigation into the stochastic nonlinearities inherent in reinforced concrete (RC) beam without web reinforcement. A series of specimen tests were conducted with a static monotonic four-point bending regime. Three kinds of RC beams (total of 27 specimens) without web reinforcement of three shear span-depth ratios of 5.1, 4.6 and 4.0 were designed. Each kind of beams had 9 samples. All beams were constructed in the same condition and at the same time. Specifically, the materials (both concrete and reinforcement bars) used in the beams were derived from the same batch, and the same testing program was performed during the experiments. Statistical nonlinearity responses to beams with three shear span-depth ratios, including the strain-deflection curves of longitudinal reinforcement bars, crack patterns, failure modes, and load-deflection curves were obtained from the tests. Different failure modes occurred in the beams with the same shear span-depth ratio. The probabilities of different failure modes of RC beams without shear reinforcement were statistically calculated based on the test results. It is found that the randomness of the mechanical properties of the materials results in the stochastic initial damage distribution and the subsequent stochastic nonlinear evolution of the beams. In addition, the shear span-depth ratio is an important parameter, which significantly affects the stochastic failure mode in the investigated members.