Behavior and design of GFRP bar adhesive anchors under direct tension for deteriorated concrete bridge barrier replacement.

This article focuses on the experimental investigation and analytical modeling of post-installed glass fiber-reinforced polymer (GFRP) bar adhesive anchors used to replace deteriorated concrete bridge barriers, particularly under freeze-thaw conditions. The study involved 120 GFRP bars of varying diameters and surface types (sand-coated and ribbed) anchored in steel-reinforced concrete slabs using two commercial epoxy adhesives, exposed outdoors over one winter in Canada. Results showed predominant pullout failure modes rather than concrete cone failure, with pullout capacity increasing with embedment depth up to 200 mm but less so beyond that, and bond strength decreasing as embedment depth increased. A regression-based analytical model was developed to predict ultimate pullout loads, providing design recommendations applicable for embedment depths between 100 and 250 mm and concrete compressive strength around 40 MPa. The study highlights the importance of considering freeze-thaw effects on adhesive anchors' durability and suggests further research for extended environmental exposure and varied parameters.