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

The application of post-installed GFRP bars is notably illustrated in replacing deteriorated bridge barriers. Fourteen steel-reinforced concrete slabs were fabricated, into which 120 GFRP bars were anchored using epoxy adhesive. These anchored GFRP bars were exposed to outdoor conditions throughout one winter to assess the impact of freeze-thaw cycles before undergoing testing to evaluate their ultimate pullout load. The experimental program included two types of adhesives, various diameters of bars, two categories of GFRP bars (sand-coated and ribbed-surface), and three nominal embedment depths for each bar diameter. For each bar combination, five identical samples were constructed. The predominant observed failure modes were pullout failures, which contributed to the development of an analytical model. A regression analysis was conducted to investigate the influence of embedment depth and bar diameter on pullout capacity, resulting in a best-fit formula that may be used in design practices.