Comparative Study of Corroded Reinforced Concrete (RC) Elements Retrofitted with Strain-Hardening Cementitious Composites (SHCCs) and Fiber-Reinforced Polymers (FRPs) Using Nonlinear Finite Element Analysis

Abstract

This thesis presents a comparative Finite Element Analysis (FEA) of two advanced retrofitting techniques applied to reinforced concrete elements deteriorated due to steel corrosion and concrete carbonation. It investigates the nonlinear behavior of reinforced concrete (RC) elements, including corroded specimens, which have been retrofitted with Strain-Hardening Cementitious Composites (SHCCs) and Fiber-Reinforced Polymers (FRPs). The study is based on finite element simulations aimed at evaluating the effectiveness of these two strengthening techniques in terms of load-bearing capacity and ductility. A comparative analysis was conducted between the numerical simulations and actual experimental results from four-point bending tests, carried out as part of a previous and ongoing research project. More specifically, the program involved the analysis of six different specimen configurations, including plain concrete, SHCC, reinforced, corroded, and SHCC or GFRP-retrofitted elements, with a single and double reinforcement. Increasing the reinforcement ratio improved both the load-bearing capacity and, more importantly, the deformability of the elements. The results demonstrated that corrosion significantly reduces the load-bearing capacity, while the application of SHCC and FRP can not only restore but exceed the original strength of the elements. SHCC exhibited greater ductility and energy absorption, while FRP provided higher peak strength but less ductile post-peak behavior.