Detection in RC beams damaged and strengthened with NSM CFRP/GFRP rods by free vibration monitoring

This paper intends to deepen the topic of damage detection based on non-destructive tests (NDT) for the assessment of the dynamic behavior of RC beams damaged and strengthened both with near-surface mounted (NSM) Carbon and GlassFRP rods. The NSM strengthening with fiber-reinforced polymer (FRP) rods of damaged reinforced concrete (RC) beams is a viable alternative to the traditional strengthening with externally bonded (EB) FRP strips or sheets. In this paper, static tests were foreseen on RC beams to create cracking, and successively, the RC beams strengthened with NSM CFRP and GFRP rods were still investigated using free vibration tests at different loading levels until failure. The purpose of this research is to compare the response of two different types of strengthening of damaged RC beams based on the strength of CFRP and GFRP rods until failure modes. At different steps of loading, the behavior of beams under experimental vibrations has been monitored by frequency response function (FRF) diagrams. Finally, a discussion of the results is presented.