NSM CFRP laminates for the shear strengthening of high strength concrete beams

Abstract

The effectiveness of the Near Surface Mounted (NSM) shear strengthening technique with Carbon Fiber Reinforced Polymer (CFRP) laminates applied in relatively high-strength concrete beams was assessed by experimental research. Six NSM shear strengthening configurations (three CFRP orientations and two levels of CFRP percentage) were applied in T cross section Reinforced Concrete (RC) beams with a steel stirrups percentage of 0.10% (ρsw = 0.10%). Four of these NSM configurations were also applied in beams with ρsw = 0.16%. The concrete of the beams had a compressive strength of 59.4 MPa at the age of beam tests. The main results of this experimental research are presented and analyzed in terms of the structural behaviour of the beams, failure modes and performance of the NSM technique with CFRP laminates. The results showed that NSM shear strengthening technique with CFRP laminates has a high performance in RC beams with high-strength concrete, not only in terms of increasing the load carrying capacity of the beams but also in mobilizing more effectively the tensile properties of the CFRP.