Flexural Strengthening of RC Beams with Steel-Reinforced Grout: Experimental and Numerical Investigation

This paper presents an investigation, both experimental and analytical, on RC beams that are strengthened in flexure using externally bonded steel-reinforced grout (SRG) composites. An experimental investigation was conducted on four reinforced concrete beams: one unstrengthened and three strengthened with SRG. The study parameter was the presence or absence of mechanical anchors. Test results emphasize the efficiency of the SRG system in terms of strength and ductility and evidence that the use of the anchors is useful only in reducing the strains of the strengthening system. A numerical model founded on a finite-element procedure, developed through Abaqus CAE version 6.14, is proposed. The SRG-to-concrete interface was reproduced by a cohesive model and a bilinear local bond-slip law was adopted. The implemented numerical model was verified by a comparison between its predictions and test results in terms of ultimate loads and load-deflection diagrams. Finally, through a parametric analysis, run by the numerical model, the influence of the main parameters on the structural performances of an SRG-strengthened RC beam was investigated and a predictive relationship for the fiber strain at debonding is proposed.