Recent global tensions and conflicts between countries have highlighted the need for protective structures that can withstand projectile impacts of high energy and high momentum. The impact of such projectiles on critical infrastructure can have severe consequences for both the population and environment. In view of this, the critical structures need to be designed to offer adequate resistance for better protection. Relatively thicker reinforced concrete structural components are common in nuclear plants, shelters both for civilian and strategic structures to provide protection. Resistance of these target structures varies depending on factors such as strength of concrete and reinforcement, configuration of reinforcement and distribution within the structure. Three-dimensional numerical simulations were performed on a thicker protective RC slab against a 500 kg heavy projectile with impact velocity of 355 m/s. Two reinforcement configurations, namely radial and grid types, were considered in the impact simulations. Holmquist, Johnson and cook (HJC model) has been adopted to simulate the high strain rate behaviour of concrete and steel rebars have been modelled using Johnson–cook constitutive model. It is observed through numerical response of the target slabs that radial type configuration of reinforcement performed better than grid type. This paper presents the details of three-dimensional finite element modelling using ABAQUS and responses are also discussed in detail.