Laboratory full-scale test on the bond property of GFRP anchor to concrete

Glass fiber reinforced polymer (GFRP) bolt, which has excellent mechanical properties and corrosion resistance, is gradually replacing metal bolt in rock and soil anchoring, compared with traditional reinforced bolts and other composite materials with high cost. In the current study, the influence of anchorage length and anchorage mode on the bonding property of bolt and concrete was investigated, and the stress mechanism of glass fiber bolt was analyzed based on the tensile test of a full-size laboratory sample. The results show that the failure modes of GFRP anti-floating anchor were pull-out failure and fracture failure, the ultimate bearing capacity of mechanical anchorage was noted as 1.08-1.24 times that of linear anchorage. Under the same anchorage method, with the increase of anchorage length, the relative displacement and the proportion of load bearing in the easing section of the bolt load-displacement curve decreased; thus, the load-displacement curve of the anchor in the form of mechanical anchorage was smoother. With the increase of load, the main load bearing mode of the bolt-concrete interface changed from the interface friction force and chemical adhesive force to the mechanical bite force, and then the interface concrete was broken, and the concrete no-acting zone was transformed into the acting zone until the bolt was damaged. Anchor had a maximum anchorage length beyond which the bearing capacity of the anchors increased minimally. Comparing the calculation formulas of anchor length under different national standards, it was suggested to use Chinese or European standards to calculate anchor length.