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Abstract
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One of the ways to confront the problem of debonding failure of externally-bonded carbon
fiber reinforced polymers (CFRP), used for strengthening of steel members, is to provide a
proper and practical bonding detail. If the high stress-concentration zones of the bonded strip
such as curtailment points of CFRP or member discontinuities are suitably detailed or
reinforced, then bonding resistance will be improved. This paper describes experimentally the
methods which successfully prevent the premature debonding failure of externally-laminated
steel members. The double-lap shear test set up has been chosen as a frame work to compare
the results. Therefore bond zones includes shear stresses and peel stresses. The mechanical
clamps in different arrangements were examined as a bond-enhancement detail. Also, the
effect of the length of the CFRP laminate was investigated along with different types of end
mechanical anchorage. Finally, a simple and efficient bonding enhancement method has been
proposed, in the form of overlapping the critical debonding zones using steel plates. The test
results show that both the overlapping and clamping methods considerably increase the
bonding resistance, but the former method is preferable because of its simplicity for
installation and because in this case further increase of strength is obtained.
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