New anchorage technique for NSM-CFRP flexural strengthened RC beam using steel clamped end plate

Using appropriate techniques, or systems, is mandatory to strengthen those elements, such as the Near Surface Mounted (NSM)-Carbon Fiber Reinforced Polymer (CFRP). The goal of this paper is to find a new mechanical anchor system to clamp the NSM-CFRP strip at the end of the beam and prevent the end cover separation of the CFRP strip to increase the ultimate beam capacity load. This technique is based on using a steel plate at the end of the beam. A total of eleven reinforced concrete beams were constructed with concrete compressive strength of 35 MPa and dimensions of 250 mm x 200 mm x 1600 mm (height x width x length) and divided into three groups (control samples, beams with CFRP, and beams with CFRP strips and plate steel clamped). The beams were strengthened with one, two, and three CFRP strips. The main parameters studied were the type of NSM-CFRP strip fixation technique and the number of NSM-CFRP strips used. The test results show that the use of a steel plate at the end with horizontal CFRP strips in the beam is more efficient in increasing the ultimate load capacity, deflection behavior, stiffness, and toughness compared to NSM-CFRP strengthened beams. (C) 2020 Elsevier Ltd. All rights reserved.