Experimental investigation of strengthening of RC one-way slabs using NSM and hybrid techniques under impact loading

Abstract

Reinforced concrete (RC) slabs are often subjected to impact loads. Due to a relatively low tensile strength and energy dissipating characteristics, the impact resistance of slabs is considered poor. Over the last few years, strengthening RC slabs with externally bonded reinforcement (EBR) methods has become a conventional technique. In this paper, six RC one-way slabs are prepared and experimentally investigated under impact loading. Since failure in slabs under impact loadings was in the form of punching shear, two new techniques are proposed to strengthen slabs against impact loads. These techniques include near surface mounted (NSM) and hybrid with high strength reinforcement (HSR) bars and carbon fibre reinforced polymer (CFRP) strips in the form of transverse, longitudinal and diagonal strengthening methods. The experimental results demonstrated that the above-mentioned strengthening techniques in one-way slabs lead to a change in the type of failure, the change of crack patterns and slabs failure. The mentioned strengthening methods lead to an increase of load carrying capacity and increase of dissipated energy.