• CFRP strengthened continuous concrete beams.

      El-Refaie, S.A.; Ashour, Ashraf F.; Garrity, S.W. (2003-11)
      This paper reports the testing of five reinforced concrete continuous beams strengthened in flexure with externally bonded carbon-fibre-reinforced polymer (CFRP) laminates. All beams had the same geometrical dimensions and internal steel reinforcement. The main parameters studied were the position and form of the CFRP laminates. Three of the beams were strengthened using different arrangements of CFRP plate reinforcement, and one was strengthened using CFRP sheets. The performance of the CFRP-strengthened beams was compared with that of an unstrengthened control beam. Peeling failure was the dominant mode of failure for all the strengthened beams tested. The beam strengthened with both top and bottom CFRP plates produced the highest load capacity. It was found that the longitudinal elastic shear stresses at the adhesive/concrete interface calculated at beam failure were close to the limiting value recommended in Concrete Society Technical Report 55.
    • Sagging and hogging strengthening of continuous reinforced concrete beams using CFRP sheets.

      El-Refaie, S.A.; Ashour, Ashraf F.; Garrity, S.W. (2003-07)
      This paper reports the testing of 11 reinforced concrete (RC) two-span beams strengthened in flexure with externally bonded carbon fiber-reinforced polymer (CFRP) sheets. The beams were classified into two groups according to the arrangement of the internal steel reinforcement. Each group included one unstrengthened control beam. The main parameters studied were the position, length, and number of CFRP layers. External strengthening using CFRP sheets was found to increase the beam load capacity. All strengthened beams exhibited less ductility compared with the unstrengthened control beams, however, and showed undesirable sudden failure modes. There was an optimum number of CFRP layers beyond which there was no further enhancement in the beam capacity. Extending the CFRP sheet length to cover the entire hogging or sagging zones did not prevent peeling failure of the CFRP sheets, which was the dominant failure mode of beams tested.