Performance assessment of reinforced concrete columns under vehicle impact load using P-I diagram

P-I diagrams are widely used for structures subjected to blast loads. In the same manner, structures subjected to vehicle impact load, such as bridge columns, could potentially take advantages of the P-I diagram if the dynamic characteristics of vehicle impact load and bridge columns are well considered. In the paper, the performance of bridge columns and hence the use of P-I diagram is evaluated under vehicle impact load. The main tasks of the paper are (1) to determine the dynamic characteristics of vehicle impact load through finite element method, and three simplified load shapes are obtained including isosceles triangle, right triangle, and rectangular shapes; (2) to investigate structural failure modes under various shear-bending ratios and impact loads; (3) to establish the damage index based on the residual axial capacity of bridge columns and to obtain P-I diagrams at different damage levels of bridge columns under vehicle impact load; (4) to parametrically analyze the effects on the impulse asymptotic and the peak load asymptotic of P-I diagrams, including column diameter, stirrup reinforcement ratio, longitudinal reinforcement ratio, and strength of the concrete. Finally, a simplified calculation method of P-I diagrams is proposed to evaluate the performance of bridge columns under vehicle impact load.