Experimental study on failure modes of MF-CFRP strengthened steel beams

Recently, strengthening of structures using Fiber Reinforced Polymer (FRP) has received the great attention of researchers. Shear and normal stresses intensity are two important factors which cause Carbon Fiber Reinforced Polymer (CFRP) end debonding in strengthened steel beams. To this end, flexural strengthening of steel beams by Mechanically Fastened- Carbon Fiber Reinforced Polymer (MF-CFRP) is one of the methods which delays this phenomenon. This research aims to study various details of mechanical fasteners and their effects on the structural behaviors of steel beams. In this study, six laterally unbraced steel I-beam specimens were tested and four different mechanical fastener details were used for CFRP end-anchoring using steel sections and bolts. The results showed that the proposed technique improved the structural characteristics of strengthened beams and reduces the strain on CFRP strips, significantly. The observed strain reduction on CFRP strips of the anchored specimens were seen up to %60 (in elastic region) and up to %30 (in plastic region) in comparison by the non-anchored specimens. Application of different types of end-fasteners influenced the initiation and sequence of CFRP failure modes considerably. (C) 2019 Elsevier Ltd. All rights reserved.