The influence of load transfer medium creep on the load-carrying capacity of the bond-type anchors of CFRP tendons

• Published in: Construction & building materials Vol. 206; pp. 236 - 247
• Main Authors: Zhuge, Ping, Jie, Zhi-yu, Zhang, Zi-hua, Ding, Yong, Hou, Su-wei
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 10.05.2019; Reed Business Information, Inc. (US)
• Subjects: Anchor; Bond-type; Bonds (Securities); Carbon fiber reinforced polymer (CFRP) tendons; Carrying capacity; Creep; Epoxy resins; Polymer industry; Polymers; Reinforced plastics; Residual shear stress; Carrying capacity; Anchor; Creep; Residual shear stress; Carbon fiber reinforced polymer (CFRP) tendons; Bond-type
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2019.02.017

•A new shear stress distribution model is proposed for the bond-type anchor.•A carrying capacity evaluation method of the anchor is established and verified that considers medium creep.•The creep of the epoxy resin medium can significantly reduce the carrying capacity of the anchor.•The influence of medium creep can be eliminated by increasing the preset load or anchorage length. The epoxy resin used as a load-transfer medium (LTM) to fill the bond-type anchors of carbon fiber reinforced polymer (C225FRP) will creep under three-dimensional compressional conditions, thereby decreasing the carrying capacity of the anchorage. In this paper, a shear stress distribution model is proposed for the tendon–LTM bonding interface in the anchorage zone of CFRP tendon bond-type anchors. Based on this distribution model, a model for evaluating the load-carrying capacity of such anchorages is established after considering LTM creep. Creep deformation data were obtained via model tests of an anchorage epoxy resin LTM subjected to three compressive magnitudes of stress under lateral restraint conditions for 3 years. The influence of LTM creep on the load-carrying capacity of the anchors is evaluated, and theoretical methods for eliminating the negative effect of the LTM creep of the anchor were proposed. The two load-carrying capacity prediction models established before and after considering LTM creep were verified by experiments. The experimental results pertaining to load-carrying capacity are in good agreement with the theoretical prediction; the creep strain of the LTM will reach 0.004 and 0.038 under axial compressive stresses of 50 MPa and 250 MPa, respectively, and lateral restraint conditions. LTM creep will lead to an obvious reduction in the radial compressive stress of the bonding interface, and the loss of the load-carrying capacity of the anchorage can reach 12%. Increasing the axial preset load acting on the LTM or extending the length of the anchor can counteract the adverse effects of creep.