Components interaction mechanism and strength of axially loaded FRP-confined concrete stub columns from energy path perspective

A thorough understanding of the interaction mechanism between the concrete core and fiber-reinforced polymer (FRP) jacket in FRP-confined concrete columns is crucial for accurate prediction of compressive strength . This paper investigated the interaction mechanism between the components from the perspective of energy path. Firstly, the theoretical expression for the energy paths in FRP-confined concrete columns was derived based on the thermodynamic theory. Furthermore, the energy paths of FRP-confined concrete columns with different numbers of FRP jacket layers and concrete strengths were conducted experimentally. The results indicated that the energy path correlates with the axial stress in the concrete and exhibits more sensitive to changes in the elastic modulus of the FRP jacket as well as the D / ratio. The confinement effectiveness of the FRP jacket was found to be more pronounced for specimens with smaller concrete dominance indicators ( K ), which are determined by the D / t ratio and the concrete strength. Based on both theoretical analysis and experimental results, an energy path–based compressive strength model for FRP-confined concrete was proposed. The model was validated against an experimental database. The results suggest that the proposed model outperforms previous models in terms of accuracy.