Experimental investigations of repair of pre-damaged steel-concrete composite beams using CFRP laminates and mechanical anchors

This paper investigates the flexural performance of pre-damaged steel-concrete composite beams repaired using externally-bonded carbon fiber-reinforced polymer (CFRP) laminates with and without mechanical anchors. A total of 10 beams were prepared, one beam was left undamaged, whereas nine beams were artificially damaged by cutting different U-shaped notches in the bottom flange at the beams’ mid-span that resulted in 45%, 73% and 100% losses in the flange thickness. Three damaged beams were not strengthened, whereas six damaged beams were repaired in flexure using externally-bonded CFRP laminates with and without mechanical anchors. The load-carrying capacities of the unstrengthened beams with damage states of 45%, 73% and 100% were approximately 11%, 23%, and 50% lower than that of the control-undamaged beam, respectively. The CFRP repair schemes were capable of restoring the original load capacity of the damaged beams with the lower damage state of 45%. For the beams with the higher damage states of 73% and 100%, the repair schemes could restore a maximum of 81% of the original load capacity. The inclusion of mechanical anchors in the repair regime improved the strength gain from 15% to 19% and from 46% to 63% for the beams with 45% and 100% damage states, respectively, relative to the strength of the corresponding damaged-unstrengthened beam.