THE FAILURE MODES OF CONCRETE BEAMS STRENGTHENED WITH NEAR SURFACE MOUNTED FRP BARS

Focusing on the failure modes, 5T concrete beams with different anchorages, surface characters, materials of FRP bars, strengthened with near surface mounted FRP (fiber reinforced polymer) bars, are used in flexural experiment. It is shown that the bonding failure happens in the strengthened beams without anchorage, and those with plain GFRP bars and CFRP bars. The ultimate load is influenced by anchorage and surface characters of FRP bars; the yield load and the ultimate load are larger in beams strengthened with CFRP bars. The coeficient of utilization of FRP bar is larger for beams strengthened with ribbed FRP bars and anchorage. Therefore, it is most effective to strengthen beams with ribbed GFRP bars and anchorage.