Experimental Study On RC Beams Shear Strengthened With NSM CFRP Strips

As more and more old concrete structures need to be repaired, a new technology strengthening structures with Near Surface Mounted (NSM) FRP ,develops rapidly in recent years., By this technology, beams are strengthened with FRP inserted into grooves cut in the surface of concrete beams. This technology offers several advantages over externally bonded FRP strengthening, and has a promising development both in application and research.Although the technology of NSM FRP strengthening has become a hot area of researching in recent years, most of the research is about the bonding mechanism and flexural strengthening. On the other hand, little work was carried on the NSM FRP shear strengthening, and no papers about this topic has been published in china till now.On the basis of the tests of 9 RC beams, this thesis studied the shear performance of the RC beams strengthenied with NSM CFRP strips. It describes the process and phenomenon of the experiment in detail, studies and analyses the failure modes and shear strength of the test beams. The test also shows that NSM CFRP shear strengthening strips are much more effective than the externally bonded one. As the results of the tests, shear capacity of the beams with NSM CFRP strips on sides increased 86% at most compared to the beams without shear reinforcement. The three main failure mechanism of beams shear strengthened with NSM CFRP strips are difined and disscussed. The failure sphenomenon and factors affect the shear capacity is also described and discussed for each mechanism. Finally, a new simple formula is developed to calculate the shear capacity of NSM CFRP shear strengthened beam which failes for Splitting of Whole CFRP-Concrete Cover.