Seismic retrofitting of reinforced concrete columns using carbon fiber reinforced polymer (CFRP)

ÖZCAN O., BİNİCİ B., Özcebe G.

1st Asia-Pacific Conference on FRP in Structures, APFIS 2007, Hong Kong, China, 12 - 14 December 2007, vol.1, pp.193-198 identifier

  • Publication Type: Conference Paper / Full Text
  • Volume: 1
  • City: Hong Kong
  • Country: China
  • Page Numbers: pp.193-198
  • Keywords: Axial load effect, CFRP, Pre-damage, RC columns, Repair, Strengthening
  • TED University Affiliated: No


© 2007 International Institute for FRP in Construction.Reinforced concrete columns with non-seismic detailing are often vulnerable to the effects of a major earthquake. In this study, the structural behaviour of undamaged and moderately damaged columns, which were retrofitted with carbon fiber reinforced polymers (CFRP) is investigated. The experimental program consists of four specimens having inadequate tie spacing, 90 degree hooks and plain reinforcing bars that were tested under lateral cyclic displacement excursions under a constant axial load of approximately 27% of the axial load carrying capacity. One reference specimen without any strengthening and one strengthened specimen with strengthening but without any pre-damage were tested. In addition, two similar specimens tested to moderate damage level of 2% drift ratio were repaired and retested. In one of the pre-damaged columns the repairing process was performed in the presence of constant axial load. The main parameters investigated in this study were the presence of axial load on the column during repairing, effect of pre-damage on ultimate displacements and the effect of CFRP wrapping on strengthened and repaired columns. The ultimate drift ratio for retrofitted columns increased to 6% which was only 3.5% for the reference column. Severe stiffness degradation was observed in both of the repaired columns due to the moderate level of pre-damage. For the repaired columns, the presence of the axial load during repairing did not significantly affect the ultimate drift ratio significantly however the enhancement in strength was not observed as compared to its companion specimen.