An equivalent fracture energy concept for nonlinear dynamic response analysis of prototype RC girders subjected to falling-weight impact loading

In order to establish a rational verification method for each limit state (mainly the serviceability and ultimate limit states) in the case of impact-resistant reinforced concrete structures, an experimentally-based study using not only small-scale but also prototype models should be conducted. However, it is not easy or economical to conduct prototype experiments. If a satisfactory numerical analysis method could be established then it would be easier to perform than experiments, due to the advances in computer technology. However, it is not easy to numerically analyze prototype structures under impact loading by means of 3D elasto-plastic finite element (FE) analysis method because very large matrices must be handled. Here, in order to establish a modified method for the tensile strength of the concrete so as to be able to satisfactorily perform the analysis using a coarse mesh, an equivalent tensile fracture energy concept for the concrete elements is proposed and its applicability is investigated by comparing with the experimental results. From this study, it is shown that even though a coarse mesh is used for the prototype reinforced concrete girder, similar results to those using a fine mesh can be obtained and these results are in good agreement with the experimental ones.