Shear reinforcement of steel I-beams using CFRP composites

Abstract

This paper presents an investigation on the shear strengthening of steel I-beams with carbon fiber-reinforced polymer (CFRP) materials, particularly using SikaWrap® - 600, and its bonding with steel surfaces using epoxy Sikardur® - 300. Six CFRP installation configurations were tested on a 6” x 3” recycled S235 I-beam (1.3 m) under four-point bending. Configurations consisted of bonding CFRP wrap to the web only, to the web and radii of the beam, and wrapped all around the beam in both a vertical and diagonal orientation. Vertical and diagonal orientation configurations increase the shear area of the web of the steel section by 140 mm2 and 170 mm2, respectively. It was shown that 1.2 mm CFRP strengthening material has the potential for enhancing shear strength at yield by a minimum of 21.42% (for configuration 1) and up to a maximum of 37.5% (for configuration 4). This upper limit enhancement would be equivalent to welding a 2.8 mm S275 steel plate using EN 1993-1-1:2006 guidelines.