Dynamic Reaction and Damage Evaluation of Reactive Powder Concrete Strengthened Reinforced Concrete Columns Subjected to Explosive Load

China has an existing building area of 80 billion square meters, where reinforced concrete structures have a large quantity and a wide surface area. The risk of structures being subjected to blast loading is relatively high. Reactive powder concrete has the specialties of ultra-high toughness, super strength, and a high strength to ponderance ratio. Reinforced concrete (RC) structures strengthened by RPC are called RPC-RC structures, which can easily elevate the explosive load resistance of building structures while also strengthening the building. It is a significant method used in avoiding the collapse of structures under explosive loads. The dynamic reaction and damage evaluation approaches of RPC-RC columns under explosive load have not been deeply studied. For addressing this issue, numerical simulation of RPC strengthened RC columns under explosive load was carried out by LS-DYNA (R10), and the correctness of the numerical simulation was verified by comparing it with relevant experimental results. In this paper, a finite element model of an RPC-RC column was established, and the main factors affecting the anti-explosion performance of an RPC-RC column were studied. The influence of the RPC reinforcement layer parameters (RPC thickness, RPC strength, longitudinal reinforcement ratio, and stirrup ratio) on the dynamic reaction and damage degree of RPC-RC columns was examined. The consequences indicated that the failure mode of the columns after RPC reinforcement can alter from bending shear damage to bending damage. As the thickness and strength of the RPC increases, the longitudinal reinforcement ratio increases, the stirrup ratio increases, and the maximum horizontal deformation of the center point of the RPC reinforced RC columns decreases. For RPC-RC columns with a height of 3–4 m and a width of 300–400 mm under blast loading, columns with an axial compression ratio greater than 0.3 will collapse, while columns with an axial compression ratio less than 0.3 are less likely to collapse. In the light of the calculation outcomes, a formula for reckoning the damage index of RPC-RC columns was proposed, taking into account factors such as proportional distance, axial compression ratio, RPC thickness, longitudinal reinforcement ratio, and stirrup ratio.

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