Influence of fabrication techniques, impregnation processes, and workmanship quality on the bonding performance of FRP anchors

This study examines the behavior of fiber-reinforced polymer (FRP) anchors as a method to mitigate premature debonding of FRP strips. The research focuses on the influence of fiber impregnation techniques in dowel regions, considering the effects of hole cleanliness, workmanship quality, and testing under confined and unconfined conditions. A key aspect of this study is the investigation of impregnation procedures performed under confined conditions, an area that has received limited attention in previous research. The experimental program included three large-scale concrete slabs (1250 × 1550 × 250 mm3) and twenty-seven FRP anchor specimens subjected to pull-out tests. The results indicate that fully impregnated anchors exhibited the highest capacity, whereas non-impregnated anchors in the dowel zone showed a significant reduction in performance. Bond strength under confined conditions, typically governed by bond failure, was approximately 50% higher than in unconfined scenarios, where concrete cone failure was predominant. Furthermore, the findings suggest that dowel inclination angles exceeding 15° led to a considerable reduction in pull-out capacity. Analytical models were developed to predict anchor capacity under varying loading conditions, highlighting the need to align modeling approaches with anticipated failure modes. Additionally, thorough cleaning of anchor holes increased load-carrying capacity by up to 20%, emphasizing the importance of proper installation procedures. This study contributes to the optimization of FRP anchor design and installation for improved structural performance.