A new bond-slip model for adhesive in CFRP–steel composite systems

Abstract Debonding of CFRP from steel surface is an important issue in the field of strengthening of steel structures. In this paper, a new method for analysis of bonded connections of CFRP and steel substrates is presented. This method simulates the connection via a series of equivalent discrete springs. In this approach, simple closed-form solutions are derived to calculate total elastic stiffness as well as effective elastic bond length of a plate bonded to a rigid substrate. Furthermore, a new bond-slip model is suggested by adding a plastic part to the previous bond-slip curve. In this model, initial stiffness is determined from elastic properties of adhesive. Two other parts are defined in such a way that the area under the curve is equal to interfacial fracture energy. Comparison of results obtained from the proposed model and experimental data shows that ultimate debonding load may be accurately estimated by the proposed model. In addition, load–displacement curve obtained by the present model is quite comparable to experimental curves. Moreover, effective bond length shows good agreement with those determined from experimental tests. In this model, unlike some previous bond-slip models, ultimate debonding load is independent from adhesive thickness.

[1]  Riadh Al-Mahaidi,et al.  Bond–slip models for double strap joints strengthened by CFRP , 2010 .

[2]  A. Carpinteri,et al.  Modelling the FRP-concrete delamination by means of an exponential softening law , 2011 .

[3]  Zhishen Wu,et al.  Full-range behavior of FRP-to-concrete bonded joints , 2004 .

[4]  Maged A. Youssef.  Analytical prediction of the linear and nonlinear behaviour of steel beams rehabilitated using FRP sheets , 2006 .

[5]  J. Teng,et al.  BEHAVIOUR OF FRP-TO-STEEL BONDED JOINTS , 2005 .

[6]  Jin-Guang Teng,et al.  Finite element prediction of interfacial stresses in structural members bonded with a thin plate , 2010 .

[7]  Michael C. Griffith,et al.  Interfacial stress transfer of near surface-mounted FRP-to-concrete joints , 2008 .

[8]  R. N. Swamy,et al.  Unified analytical approach for determining shear capacity of RC beams strengthened with FRP , 2011 .

[9]  Denvid Lau,et al.  Experimental study of hybrid FRP reinforced concrete beams , 2010 .

[10]  J. Cognard,et al.  Numerical analysis of edge effects in adhesively-bonded assemblies application to the determination of the adhesive behaviour , 2008 .

[11]  Abdelouahed Tounsi,et al.  Interfacial stress analysis of steel beams reinforced with bonded prestressed FRP plate , 2008 .

[12]  M. Hildebrand,et al.  Non-linear analysis and optimization of adhesively bonded single lap joints between fibre-reinforced plastics and metals , 1994 .

[13]  J. J. Cheng,et al.  Cohesive zone with continuum damage properties for simulation of delamination development in fibre composites and failure of adhesive joints , 2008 .

[14]  Riadh Al-Mahaidi,et al.  Bond characteristics between CFRP and steel plates in double strap joints , 2005 .

[15]  Alireza Maheri,et al.  Seismic performance of ordinary RC frames retrofitted at joints by FRP sheets , 2010 .

[16]  Riadh Al-Mahaidi,et al.  Experimental and finite element analysis of a double strap joint between steel plates and normal modulus CFRP , 2006 .

[17]  Stephanie L. Walkup,et al.  Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures (ACI 440.2R-02) , 2005 .

[18]  X. Zhao,et al.  State-of-the-art review on FRP strengthened steel structures , 2007 .

[19]  Jin-Guang Teng,et al.  Bond-slip models for FRP sheets/plates bonded to concrete , 2005 .