Load transfer behavior of BFRP anti-floating anchors based on field pull-out tests
The basalt fiber reinforced polymer(BFRP)anchor rod has advantages such as lightweight,high tensile strength and excellent corrosion resistance.This study pioneers the application of BFRP anchor rods in the basement anti-floating of a coastal hospital.The ultimate pull-out tests were conducted on five full-threaded BFRP anti-floating anchor rods with different anchorage lengths and diameters.The failure modes of the anti-floating anchor rods were analyzed,and the load-displacement relationship of the anchor rod and the anchor body was determined.The distribution of the axial force and the shear stress along the depth of the BFRP anchor rod was investigated,and the failure mechanism of BFRP anchor rods was discussed.The research reveals that:(1)The ultimate pull-out capacity of both groups of BFRP anti-floating anchor rods exceeds 400 kN,fully satisfying the anti-floating requirements of the project.(2)With the increase in the anchorage length and the rod diameter,the ultimate pull-out capacity of the anti-floating anchor rods slightly increases,but the displacement of the rod also increases accordingly.(3)The axial stress of BFRP anchor rod is maximum at the hole opening and decreases with increasing the depth.The area of stress transfer extends approximately two-thirds of the anchorage length.It is limited to improve the pull-out bearing capacity of the anti-floating anchor road through increasing the anchorage length.(4)The shear stress in the BFRP anchor rod initially increases rapidly along the depth of the anchorage,and then gradually decreases after reaching a peak near the anchorage depth of 0.75 m.The peak shear stress increases with increasing the load level.The results of the study provide a foundation for the application of BFRP anti-floating anchor rods.