Enhancement of FRP Cable Anchor System: Optimization of Load Transfer Component and Full-Scale Cable Experiment

Abstract

In this study, the compressive behavior of a load transfer component (LTC) for a fiber-reinforced polymer (FRP) cable anchor system (CAS) was improved using three types of microfibers, including 8-μm-diameter and 13-μm-diameter glass microfibers and 7-μm-diameter carbon microfibers, and implemented in a full-scale 37-tendon basalt FRP (BFRP) cable. The results showed that the corresponding optimal fiber lengths for the LTCSFs were 150, 900, and 75 μm, respectively. The compressive failure of the LTC modified by single-length microfibers (LTCSFs) was caused by microfiber debonding, pullout, and fracture. The compressive strengths and elastic moduli of the LTCSFs were positively related to the microfiber content. The compressive properties of the LTCSFs could be well predicted by a cubic polynomial fitting formula with R2 > 0.99. When it was modified by multiple-length 8-μm-diameter glass microfibers (LTCMGF-8), an LTC with a hybrid ratio of 3:2 showed the optimal compressive strength and ductility. Then, to further release the radial stress of the FRP cable, a CAS with a variable-stiffness LTC could be optimized by decreasing the loading-end elastic modulus and increasing the free-end elastic modulus of the LTC. Finally, the effectiveness of the optimized variable-stiffness LTC was verified in a 37-tendon BFRP cable with a tendon diameter of 4 mm. Compared with the nominal breaking load of 761 kN, the experimental ultimate load of the BFRP cable was 766 kN and the corresponding anchor efficiency was 101%.