Simplified Anchor System for CFRP Rods

Abstract

The increased use of carbon fiber–reinforced polymer (CFRP) rods in prestressed concrete applications has been challenged by identifying a suitable anchor system. To overcome such a challenge, the design of a simplified anchor system composed of three wedges and a barrel, without a soft sleeve, is presented to duplicate the simplicity of the widely utilized anchor systems in steel strands. A numerical study and experimental verification of the simplified anchor system for a CFRP rod are presented. Three-dimensional (3D) finite-element modeling has been conducted on the anchor system consisting of isotropic steel wedges and barrel, in addition to an orthotropic CFRP rod. The wedges and barrel are modeled as elastoplastic materials of different hardness. The rod/wedge and wedge/barrel interfaces are simulated using surface-based contact models having different coefficients of friction. Two hardness levels [171 and 319 Vickers hardness numbers (VPN)] are considered for the wedges. When the softer wedges are utilized the ultimate tensile strength of the CFRP is attained. With the harder wedges the rod fails prematurely due to slippage followed by fracture. The performance of the anchor system using numerical modeling successfully describes the experimental results.