Effects of CFRP layer orientation on strengthening of hollow steel elements

Abstract

This paper studies the effects of orientation of CFRP (carbon fibre reinforced polymer) strip layers on the improvement of bearing capacity of strengthened steel-made circular hollow elements. The four point bending test was conducted, and elements were subjected to bending until failure. The improvement of bearing capacity of strengthened tubular steel elements is presented in terms of failure load, stiffness, composite beam action, and modes of failure. Beams strengthened with CFRP strips with two longitudinal layers and one layer along the periphery performed better than the beams reinforced with one longitudinal layer and two layers along the periphery.