Static Behavior of Circumferential Stress-Releasing Anchor for Large-Capacity FRP Cable

Abstract

In this study, an optimized anchor system to enhance the anchor performance of multiple-tendon fiber-reinforced polymer (FRP) cables was proposed and evaluated. The manufacture of the cables comprised 37 basalt FRP (BFRP) tendons with nominal diameters of 4 mm. Their anchor system was first studied by solving the bonding problem for each tendon. Furthermore, a novel winding device was designed to realize a variable elastic modulus for the load transfer component (LTC) with different fibers. The experimental process included evaluating the tensile properties of the cable, the strain distributions in the anchor zone and central part, and the stress-strain relationship of the cables. The optimizing effect of the anchor was evaluated by comparing the results with those of previous studies. The results showed that the anchor could effectively bear the tension behavior of the cable and avoid shear stress concentration at the loading end. It was also shown that an LTC with three slits could maintain a higher elastic modulus than one with four slits. The losses in the tensile strain of the BFRP tendons at different locations under equal loads exhibited slight differences. The inner and outer BFRP tendons experienced almost no shear lag effect. Moreover, the tensile strain of the BFRP cables in the anchor zone decreased gradually from the loading end to the free end and no evident correlation between tensile strain and the location of the BFRP tendons for equal cross sections of the anchor zone was observed. The mean axial tensile strain–fitting curve of the BFRP cables in the anchor zone exhibited good agreement with the simulated curve for a variable stiffness.