Inertial Effect on RC Beam Subjected to Impact Loads

A simply supported reinforced concrete (RC) beam only experiences sagging moment under static loads while it might experience both sagging and hogging moments under impact loads due to the inertial effect. In order to investigate inertial effect on the impact behavior of RC beam, a numerical model is developed by using the finite element code LS-DYNA. The strain rate effect of the material is considered in the numerical model. The numerical model is calibrated with the testing results of drop weight impact on RC beams available in the literature. The numerical results show that the prediction is better than some other researchers’ predictions in terms of peak impact force and peak deformation. In addition, inertial effect is quantitatively evaluated by the peak impact force and the peak hogging moment. The relationship between the peak hogging moment and the peak impact force of the beam is investigated by conducting parametric studies with regard to various net spans, impact masses and impact velocities. The empirical formulae are then proposed to predict the peak impact force and the peak hogging moment. The predications by the proposed empirical formulae are compared with the testing results and the predicted results by other formulae available in the literatures.