Effects of the bond properties of ETS-GFRP bar to concrete on the shear behavior of ETS-GFRP-strengthened RC beams

This study numerically investigates the effects of bond properties between embedded through-section-glass fiber- reinforced polymer (ETS-GFRP) bars and concrete on the performance of the reinforced concrete (RC) beams strengthened in shear with ETS-GFRP bars. The key bond parameters, including the interfacial fracture energy (G(f)), bond stiffness (K), and bond strength (tau(m)) are examined. Results demonstrate that the bond properties of ETS-GFRP bar-concrete interfaces mainly affect the postpeak behavior and ductility of the ETS-strengthened beams. The FE model considering triangle bond model for the ETS-GFRP bar-concrete interfaces can reasonably predict the load versus deflection and failure mechanism of the ETS-strengthened beam as well as the debonding process of the ETS-GFRP bars from concrete against the experimental results. The use of the flexible and ductile adhesive, which has small bond stiffness and high interfacial fracture energy, for ETS-GFRP bonding technology would lead to the large ductility of the ETS-GFRP-strengthened beams. The ETS-GFRP bar-concrete interfaces with high cohesive strength can distribute the shear cracks and limit the local debonding, encouraging the deformability of ETS-GFRP-strengthened beams.

Automated summary

This study numerically investigates the effects of bond properties between embedded through-section-glass fiber-reinforced polymer (ETS-GFRP) bars and concrete on the performance of reinforced concrete (RC) beams strengthened in shear with ETS-GFRP bars. Results demonstrate that the bond properties mainly affect the postpeak behavior and ductility of the strengthened beams. The use of a flexible and ductile adhesive with small bond stiffness and high interfacial fracture energy can lead to increased ductility of the strengthened beams. The high cohesive strength of the ETS-GFRP bar-concrete interfaces can distribute shear cracks and limit local debonding, encouraging deformability of the strengthened beams.