Numerical investigation of the behavior of precast concrete segmental columns subjected to vehicle collision

This study numerically investigates the response of precast concrete segmental columns with unbonded prestress tendons subjected to vehicle collision. Numerical models are developed using LS-DYNA and validated against experimental tests. The validated model is then used to perform intensive numerical simulations to analyze the effectiveness of prestressing level, number of segments, concrete strength, and vehicle velocity on the behavior of precast segmental concrete columns. The numerical results have shown that the effect of the initial prestressing level and the number of segments are marginal on the impact force time history but significant on the residual displacement and the damage of the column. Better self-centering capacity as well as smaller lateral displacement can be achieved on segmental columns by reducing the number of column segments and increasing the prestress level. In addition, the height-to-depth ratio of a concrete segment should be smaller than two in order to minimize an undesirable local damage at the rear side opposite the impact point. Varying concrete strength from 20 MPa to 80 MPa shows an unnoticeable change of the impact force but its effects on mitigating the damage of the columns are considerable. Last but not least, increasing the impact velocity does not always increase the peak impact force of a segmental column. It is recommended that both the peak impact force and impulse should be taken into consideration in the analysis and design of segmental columns against vehicle impact.