Behaviour of FRP-to-concrete interfaces between two adjacent cracks : a numerical investigation on the effect of bondline damage

Abstract The bond behaviour between FRP and concrete has been commonly studied using simple pull-off tests on bonded joints where an FRP plate bonded to a concrete prism is pulled at one end to induce debonding failure. Knowledge gained from such studies has been directly employed in predicting debonding failure in FRP-plated concrete beams induced by major flexural cracks, but significant differences exist between the two scenarios. The chief difference lies in the interaction between adjacent flexural cracks in a flexural member which is absent in a joint pull-off test. This interaction may be approximated using an FRP-to-concrete bonded joint where the FRP plate is pulled at both ends. This paper presents a numerical study into this bonded joint problem, with the main objective being to clarify the effect of bondline damage during slip reversals on the ultimate load. The study shows that such damage has a significant effect on the predicted bond behaviour and ultimate load when the ratio between the end loads is larger than 0.7, particularly when the bond length is reasonably large. An important implication of the present study is that in the modelling (e.g. finite element modelling) of debonding behaviour of FRP-plated RC beams where multiple cracks exist, the FRP-to-concrete interface should be represented using a bond-slip model with appropriate consideration of the damaged behaviour during slip reversals in order to achieve accurate predictions.

[1]  P. Feenstra.  Computational aspects of biaxial stress in plain and reinforced concrete : proefschrift , 1993 .

[2]  Suchart Limkatanyu,et al.  ROLE OF BOND IN RC BEAMS STRENGTHENED WITH STEEL AND FRP PLATES , 2001 .

[4]  Guangming Chen,et al.  On the finite element modelling of RC beams shear-strengthened with FRP , 2012 .

[5]  Zhishen Wu,et al.  Numerical Analysis of Debonding Mechanisms in FRP‐Strengthened RC Beams , 2005 .

[6]  J. Teng,et al.  Intermediate Crack Debonding in FRP-Strengthened RC Beams: FE Analysis and Strength Model , 2007 .

[7]  K. Neale,et al.  Fatigue of CFRPs externally bonded to concrete , 2005 .

[8]  Jian fei Chen,et al.  Anchorage strength models for FRP and steel plates bonded to concrete , 2001 .

[9]  Jin-Guang Teng,et al.  Strengthening and rehabilitation of civil infrastructures using fibre-reinforced polymer (FRP) composites , 2008 .

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

[11]  J. Teng,et al.  FRP-to-concrete interfaces between two adjacent cracks: Theoretical model for debonding failure , 2006 .

[12]  Wei He,et al.  A fracture energy based constitutive model for the analysis of reinforced concrete structures under cyclic loading , 2008 .

[13]  Scott T. Smith,et al.  FRP: Strengthened RC Structures , 2001 .

[14]  L. Bank.  Composites for Construction: Structural Design with FRP Materials , 2006 .

[15]  Zhishen Wu,et al.  Diagonal macro-crack induced debonding mechanisms in FRP rehabilitated concrete , 2006 .

[16]  K. W. Neale,et al.  EXPERIMENTAL INVESTIGATION OF BONDED FIBER REINFORCED POLYMER-CONCRETE JOINTS UNDER CYCLIC LOADING , 2003 .

[17]  P. Camanho,et al.  Mixed-Mode Decohesion Finite Elements for the Simulation of Delamination in Composite Materials , 2002 .

[18]  Jin-Guang Teng,et al.  Meso-scale finite element model for FRP sheets/plates bonded to concrete , 2005 .

[19]  D. Hordijk.  Local approach to fatigue of concrete , 1991 .

[20]  Z. Bažant,et al.  Fracture and Size Effect in Concrete and Other Quasibrittle Materials , 1997 .

[21]  Vistasp M. Karbhari,et al.  FE Investigation of Material and Preload Parameters on FRP Strengthening Performance of RC Beams, I: Model Development , 2008 .

[22]  J. Yaoa,et al.  Experimental study on FRP-to-concrete bonded joints , 2004 .

[23]  J. Blaauwendraad,et al.  Crack Models for Concrete, Discrete or Smeared? Fixed, Multi-Directional or Rotating? , 1989 .

[24]  Deric J. Oehlers,et al.  Design of FRP and Steel Plated RC Structures: Retrofitting Beams and Slabs for Strength, Stiffness and Ductility , 2004 .

[25]  J. Rots.  Computational modeling of concrete fracture , 1988 .

[26]  O. Büyüköztürk,et al.  Progress on understanding debonding problems in reinforced concrete and steel members strengthened using FRP composites , 2004 .

[27]  G.M. Chen,et al.  Finite-element modeling of intermediate crack debonding in FRP-plated RC beams , 2011 .

[28]  Scott T Smith,et al.  Intermediate crack-induced debonding in RC beams and slabs , 2003 .

[29]  Jin-Guang Teng,et al.  Mechanics of debonding in FRP-plated RC beams , 2009 .

[30]  Yail J. Kim,et al.  Fatigue Behavior of Externally Strengthened Concrete Beams with Fiber-Reinforced Polymers: State of the Art , 2008 .

[31]  Jian fei Chen,et al.  Finite Element Modelling of FRP-to-Concrete Bond Behaviour Using the Concrete Damage Plasticity Theory Combined with a Plastic Degradation Model , 2010 .

[32]  Sami H. Rizkalla,et al.  Modeling of IC Debonding of FRP-Strengthened Concrete Flexural Members , 2008 .

[33]  Yuichi Sato,et al.  Bond Stress–Slip Relationship between FRP Sheet and Concrete under Cyclic Load , 2007 .

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

[35]  J. Teng,et al.  Debonding failure along a softening FRP-to-concrete interface between two adjacent cracks in concrete members , 2007 .