An adhesive-bolt hybrid joint and its application in concrete beam reinforced with FRP bars

This study introduces an adhesive-bolt hybrid joint designed to address the challenges of connecting Fiber Reinforced Polymer (FRP) bars in concrete applications. To optimize the mechanical performance of FRP bars while addressing issues such as uneven stiffness distribution and compliance with concrete cover thickness requirements, the joint integrates the clamping force of bolts, the adhesive bonding force and the restraint provided by a sleeve. The research provides a comprehensive methodology for force analysis and joint design, focusing on minimizing anchorage length and enhancing load transfer mechanisms. The proposed joint design was validated through mechanical performance tests on both the hybrid joint and FRP reinforced concrete beams incorporating the joint. Results show that the adhesive-bolt hybrid joint meets the design criteria for FRP bar connections, effectively utilizing the superior tensile properties of FRP bars to improve the load-bearing capacity and deformation performance of FRP reinforced concrete beams. The application of this hybrid joint in FRP reinforced concrete beams illustrates its potential to enhance structural safety and performance, with observed crack widths and overall mechanical performance comparable to those of FRP reinforced concrete structures without the joint.