Assessment of the effectiveness of the NSM shear strengthening technique for deep T cross section RC beams

Abstract

The effectiveness of the near surface mounted (NSM) technique with carbon fibre reinforced polymer (CFRP) laminates for the shear strengthening of reinforced concrete (RC) beams has been demonstrated during the last decade. Analytical and numerical research indicate that the NSM technique for the shear strengthening of RC beams can be more effective if the CFRP laminates are deeper installed into the slits. However, the depth of the slits is conditioned by the thickness of concrete cover of the lateral faces of the beam. Furthermore, relatively deep slits can only be executed, by maintaining an effective bond transfer length for the CFRP laminates crossing the shear crack, if the beam’s cross section is relatively high. Therefore, an experimental program composed of a series of RC beams of relatively high T cross section web, shear strengthened according to the NSM technique with CFRP laminates, was carried out. The experimental program is described and the main results are presented and discussed.