Analytical bond strength of deformed bars in concrete confined with transverse reinforcement and FRP

To ensure the long-term stability and safety of concrete structures, it is critical to accurately analyze the internal transverse reinforcements and externally bonded fiber-reinforced polymer (FRP) confinement to bond perfor-mances of deformed bars in concrete. However, no prediction models are available for bond strength and the bond-slip response with double confinement (transverse reinforcement and FRP). To address these issues, the present study proposes a predictive model to evaluate the bond strength of deformed bars in concrete under double confinement. The focus is on determining the internal pressure at the reinforcement/concrete interface provided by the transverse reinforcement and FRP at various stages of concrete cracking. The integral absolute error (IAE) of 12.0% for the 93 experimental data from the training dataset shows that the proposed model outperforms the other models. A general model for a bond-slip response involving double confinement is pro-posed and validated, along with a design recommendation to predict the minimum FRP thickness and bond length for seismic reinforcement.

Automated summary

To ensure the stability and safety of concrete structures, it is crucial to analyze the effects of internal transverse reinforcements and externally bonded fiber-reinforced polymer (FRP) confinement on the bond performances of deformed bars in concrete. However, there are currently no prediction models available for bond strength and bond-slip response with double confinement. This study proposes a predictive model that evaluates the bond strength of deformed bars in concrete under double confinement, providing a more accurate analysis and outperforming other models based on experimental data.