Development of a new FRP anchor for externally bonded CFRP sheet/laminate to beams.

摘要

To delay the delamination of the externally bonded FRP sheet/laminate from the concrete surface and to ensure that after initial delamination the FRP continues to carry some load, a new CFRP mechanical anchor system is developed and tested in this study. The comb-shape anchor is made using an existing CFRP grid known as NEFMAC. The comb teeth are inserted into drilled holes in the concrete while the comb spine rests on the surface of the FRP sheet and is adhesively bonded to it.; A total of nine simply supported reinforced concrete beams are tested in bending to study the effectiveness of this anchor system. Four beams are strengthened with a CFRP sheet, four with a CFRP laminate and one is unstrengthened and used as control beam.; Results of the study reveal that when the anchors are spaced relatively closely, they can delay delamination and after initiation of delamination, the FRP can still carry load, while without the anchor, the FRP begins to separate from the beam as soon as delamination occurs. The developed anchor system shows promise, but further investigation is needed to determine the exact number, size and location of such anchors in order for the bonded FRP to reliably achieve its full design strength.