Dynamic impact load has an extensive application area in civil engineering, including highway, military, and marine structures. Many researchers have studied the performance of reinforced concrete (RC) columns under impact load. However, very limited work has been conducted on the effect of bundle reinforced concrete (BRC) columns subjected to lateral impact load. In this study, to examine the behavior of RC columns under impact load, numerical simulations of one with normal reinforcement distribution and three different bundles of reinforced concrete column specimens have been conducted using an explicit finite element (FE) analysis. In addition to the bundle reinforcement distribution, the parameters considered in the study are impact scenarios, impact velocity, pure axial load, and impact locations. From the numerical analysis, it has been found that bundling of longitudinal reinforcement does not only improve the impact capacity but also stabilizes the fluctuating response of impacted reinforced concrete columns. Both peak impact force and maximum lateral displacements of impacted BRC columns increase with increasing initial impact velocity. The numerical results also show that pure axial load slightly improved the impact capacity of the BRC columns. Finally, while the global failure of the RC column governs the response of repeatedly impacted BRC columns, failure characteristics of the single impacted columns are associated with local concrete damage at the impact zone.

This paper studied numerically the behavior of carbon fiber reinforced polymer (CFRP) confined bundle reinforced concrete (BRC) columns subjected to repeated impact load. To verify the numerical models with previous experimental tests, Abaqus/Explicit based nonlinear finite element (FE) model was developed. Based on the proposed FE analysis, a parametric study was conducted to investigate the effects of different factors such as CFRP confinement, eccentric axial load, bundle reinforcement arrangement, and column height on repeated impact capacity of RC column. While modeling the structural element, concrete damage plasticity (CDP) model is adopted to account for the plastic and strain rate-dependent behaviors of concrete material under impact load. From the nonlinear FE analysis result, it was found that CFRP confinement improved the impact capacity of bundle reinforced concrete column. As column height increased, the column impact resistance was found to decrease. Moreover, when the CFRP strengthened BRC column specimens were repeatedly impacted, the continuous matrix material was severely damaged, while the fiber showed only minor and gradual compressive failures.