Debonding Strength of Steel Beams Strengthened with CFRP Plates

This paper addresses the debonding strength of partial-length, adhesively bonded carbon fiber-reinforced polymer (CFRP) plates that are used to strengthen steel beams. Bonded CFRP plates tend to debond under static and fatigue loadings because of the very high stress field at the plate end. Such failures limit the application of CFRP plates. Static and fatigue tests show that the stress intensity factor governs the debonding strength. The steel/adhesive corner was the locus of debond initiation. The effects of the following parameters on stress intensity factors are discussed: plate thickness, plate modulus, bondline thickness, adhesive modulus, and adhesive spew-fillet angle. The stress intensity factors are calculated using the Betti’s law-based reciprocal work contour integral method (RWCIM). The parametric study results indicate that the stress intensity factors cannot be used to represent the severity of the corner as the adhesive spew-fillet angle (and singularity) changes. Therefore, the use of str...

[1]  Michael J. Chajes,et al.  STRENGTHENING OF A STEEL BRIDGE GIRDER USING CFRP PLATES , 2001 .

[2]  David B. Bogy,et al.  Two Edge-Bonded Elastic Wedges of Different Materials and Wedge Angles Under Surface Tractions , 1971 .

[3]  W. Carpenter,et al.  A path independent integral for computing stress intensities for V-notched cracks in a bi-material , 1987 .

[4]  M. Williams,et al.  Stress Singularities Resulting From Various Boundary Conditions in Angular Corners of Plates in Extension , 1952 .

[5]  Terry J Wipf,et al.  Repair of Steel Composite Beams with Carbon Fiber-Reinforced Polymer Plates , 2004 .

[6]  Rajan Sen,et al.  Strengthening steel bridge sections using CFRP laminates , 2001 .

[7]  R. S. Dunham,et al.  A contour integral computation of mixed-mode stress intensity factors , 1976, International Journal of Fracture.

[8]  M D Bowman,et al.  FATIGUE STRENGTH OF GIRDERS WITH TAPERED COVER PLATES. FINAL REPORT , 1995 .

[9]  M. Tavakkolizadeh,et al.  Strengthening of Steel-Concrete Composite Girders using Carbon Fiber Reinforced Polymers Sheets , 2003 .

[10]  Bryan E. Little,et al.  American Association of State Highway and Transportation Officials. Highway Drainage Guidelines American Association of State Highway and Transportation Officials. LRFD Bridge Design Specifications , 2000 .

[11]  Hamid Saadatmanesh,et al.  Fatigue Strength of Steel Girders Strengthened with Carbon Fiber Reinforced Polymer Patch , 2003 .

[12]  D. Munz,et al.  Stress singularities in a dissimilar materials joint with edge tractions under mechanical and thermal loadings , 1997 .