04-03-2014, 12:34 PM
SEISMIC RETROFITTING OF REIN FORCED CONCRETE COLUMNS USING CARBON FIBER REINFORCED POLYMER (CFRP)
Author: O. Ozcan , B. Binici and G. Ozcebe | Size: 781 KB | Format: PDF | Quality: Unspecified | Publisher: Asia-Pacific Conference on FRP in Structures (APFIS 2007) S.T. Smith (ed) © 2007 International Institute for FRP in Construction | Year: 2007 | pages: 6
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.
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