Performance of reinforced concrete composite wall systems under projectile impact

Abstract

Composite walls consist of two reinforced concrete (RC) walls with or without a filling between them. The use of RC composite walls instead of thick monolithic concrete walls can save material costs significantly. However, it is still unknown if a composite wall system with some granular filling can provide impact resistance comparable to a monolithic RC wall. The objective of this experimental study was to investigate the effect of granular fillings between the two RC walls in improving the impact potential of composite walls and compare the behavior of such walls with that of an equivalent monolithic RC wall. For this purpose, the specimens were prepared to simulate monolithic and composite RC walls. These specimens were tested with a gas gun under single and multiple/repetitive impact loading using hemispherical nose projectiles. The composite walls’ response was then studied and compared with the response of monolithic and no-filling composite walls. Test results and the analysis of the results demonstrate that the idea of using a composite wall system is very promising as the impact response of a composite wall system is much improved than a monolithic wall of the same total thickness and reinforcement. The ballistic limit of the composite wall was also found. In order to predict the ejected mass from a composite wall system, a new analytical model was proposed. There was reasonable agreement between the test results and the prediction.