Prediction of Elastic-Softening-Debonding behavior for CFRP Tendon-Adhesively bonded anchors

Abstract

The anchor for carbon fiber reinforced polymer (CFRP) tendon is a key component applied in prestressed structures using CFRP cables. The damage due to cracking and debonding in the anchor zone influences the anchor system performance significantly. On the basis of interface mechanics theory, a trilinear bond-slip law was applied to derive the theoretical models of the stress distribution, tendon slip, and ultimate bearing capacity of the adhesively bonded anchor in various loading stages. The initiation of the local debonding as well as the softening and debonding propagation were modeled. The theoretical models were assessed with respect to experimental results. The influence of variable design parameters on the anchor performance was investigated. The results show that the proposed theoretical models are valid. The interface of the adhesively bonded anchor may undergo a series of stages; from the elastic stage to the softening stage and finally to the debonding stage when subjected to an axial tensile loading. Various closed-form solutions can be derived for different stages that leads to a discovery of an effective bond length. When the bond length is within this effective length, the tensile load capacity increases with respect to the anchor length. Otherwise, the ultimate capacity can hardly be improved by increasing the bond length. The increase in axial rigidity of the bonding medium improves the effective bond length and the ultimate load capacity of the anchor. Moreover, this growth rate is influenced by the diameter of the tendon.