Flexural Behavior of Steel Beams Strengthened with CFRP Under Fire

This study presents a finite element analysis on the flexural strength of CFRP- strengthened steel beams exposed to fire. A finite element analysis software, ABAQUS, was utilized to generate the beam models. The beams with simply supported conditions were subjected to a uniformly distributed load, a midspan-concentrated load, and equal end moments. The strengthened steel beams with various lengths of CFRP were covered by a fire insulation layer. A mixed-mode cohesive law was used to describe the bonding behavior of the adhesive which was employed to bond between CFRP and the beam surface. Based on the collected data in previous studies, the bonding characteristics of the adhesive at normal and elevated temperatures were proposed. The numerical results showed that the length of CFRP and the thickness of fire insulation have a considerable influence on the flexural capacity of the CRFP-strengthened steel beam under fire. The most strengthening effect of CFRP on steel beams was observed in the case of concentrated load at midspan.