Bonding performance and load transfer characteristics of BFRP anchors: Insights from field pull-out tests

Abstract

Basalt fiber-reinforced polymer (BFRP) anchors have been gradually employed in the field of geotechnical anchorage engineering. However, there remains substantial potential for further exploration of their bonding performance and load transfer characteristics through theoretical and experimental methods. In this study, five BFRP anchors with a diameter of 32 mm and varying lengths of 2.8 m, 3.3 m, 3.8 m, 4.3 m and 4.8 m, were employed to conduct field pull-out tests. Data on pull-out load, displacement, and stress was subsequently collected. The findings indicated a strong correlation between the calculated values of axial force and shear stress derived from the analytical solution of load transfer and the measured values (the correlation coefficient is greater than 0.9), thereby validating the effectiveness of the double exponential curve shear slip model. The load-bearing capacity of the anchoring system was affected by the critical anchorage length, which was computed to be 3.64 m. The form of load–displacement curve and the failure mode of the BFRP anchoring system were governed by the anchorage length. The morphology and types of cracks within the cement slurry were found to be associated with the tensile stress field. Although pre-reinforcement of weak strata can enhance the load-bearing capacity of the BFRP anchorage system, it is also imperative for manufacturers to enhance the shear performance of BFRP anchors by optimizing surface morphology design and refining manufacturing processes.