Strengthening of corroded reinforced concrete slabs under multi-impact loading: Experimental results and numerical analysis

Abstract

Corrosion is one of the major causes of significant deterioration in Reinforced Concrete (RC) structures. Dynamic loads and local impacts can exacerbate the conditions of structures caused by corrosion. This paper investigated the dynamic behavior of RC slabs with corroded reinforcement and evaluated the effects of strengthening using externally bonded Fiber Reinforced Polymer (FRP). Five RC slabs of 1100 × 450 × 60 mm were subject to accelerated corrosion using a constant current technique. One control slab, two corroded, and two strengthened corroded slabs were tested under low-velocity impact loads. A simple yet practical macro-scale Finite Element (FE) model was developed and validated using the experimental results with an average error of 10 and 13% for positive and negative peak acceleration, respectively. The FE model employed concrete damage plasticity and accounted for the steel mass losses and the volumetric changes of the corrosion products. Finally, a parametric study quantified the relations of carbon FRP strengthening ratio and the corrosion levels. Results indicated that FRP strengthening improved the dynamic behavior of corroded slabs. The number of impacts that the slabs with 15 and 30% corrosion could take increased to 13 and 10, respectively, for the FRP strengthened slabs from 2 and 1 for the unstrengthened slabs. It was found that FRP strengthening was more effective in improving the peak acceleration behavior of the less corroded slabs.