Experimental research on the bonding and anchorage performance of glued-in GFRP rod in glubam

Fiber reinforced polymer (FRP) rod is a reasonable alternative to steel rod used in glued-in rod engineered bamboo structures, mainly attributed to its significantly higher strength-to-weight ratio and excellent corrosion resistance. However, research in this field is limited. In this study, a total of 60 glued-laminated bamboo (glubam) specimens with glued-in single glass fiber reinforced polymer (GFRP) rod were subjected to axial pull-pull tension tests. The investigation focused on the effects of anchorage length, rod diameter, and bonding length-to-diameter ratio on the anchorage performance. Test results revealed that all specimens failed due to debonding at the glubam-adhesive interface. Approximately 27% of the specimens exhibited pure adhesive failure, while about 70% of specimens experienced a mixed failure mode involving both adhesive pull-out and shear failure in glubam, and 3% of specimens exhibited splitting failure of glubam. Furthermore, the bonding strength of the glued-in glubam joints is primarily governed by the anchorage length or abonding length-diameter ratio of glued-in GFRP rods, corresponding to a negative correlation between them. In contrast, the axial stiffness of the glued-in glubam joints increases with increasing of the diameter of the GFRP rod. Based on the single-parameter correlation analysis, a strength model and an axial stiffness model were proposed for predicting the mechanical performance of glubam joints with glued-in GFRP rod, which also demonstrated good agreement with the experimental data.