An Analytical Prediction of Maximum Deflection and Concrete Contribution in Shear-Critical RC Beams Subjected to Low-Velocity Transverse Impact

Due to paucity of study of shear-critical reinforced concrete (RC) beams subjected to transverse impact, the present study proposes a validated numerical model to study the response of a simply supported rectangular shear-critical RC beams and proposes an analytical relationship to quantify the concrete contribution, maximum deflection, and peak-strain rate. The impact load is applied at the mid-span of the RC beam using a free-falling 300 kg steel weight, subjected to impact velocities of 0.5–6 m/s, and dynamic responses are extensively studied. The influence of different parameters such as the span, velocity, shear reinforcement ratio, interface, and impactor characteristics on damage of shear-critical RC beams has been studied. The results of the present study showed that presence of shear reinforcement has an inhibitory effect toward the crack propagation, and mid-span deflection can be used as a performance index for assessing the damage levels of RC beams. It is further observed that as the impact velocity increases, the peak impact force, reaction force, and mid-span deflection increase, leading to faster crack propagation and severe damage of the RC beam. However, for the same span, time lag is observed to be increasing as the velocity of impact increases. Upon studying the influence of the mass of the impactor, the heavier the impactor, the more the force transmitted to the beam will be, causing higher damage to the beam. It is worth highlighting that the analytical expressions reported in the present study can be used in analyzing and designing shear-critical RC beams.