The paper considers the flexural aspect of steel beam at high temperature and then reinforced with the externally bonded carbon fiber-reinforced polymer (CFRP) plates. The research problem under consideration is the post-fire structural performance and the effects of notches that are the key concentration points of stress, causing structural failure. Nine beam specimens that included control specimens were tested under four-point bending; the beam specimens were exposed to high temperatures (500degC and 700degC). The control beam was retained by more than 90 percent of the beams after they were exposed to 500degC, which meant that they could be reused when retrofitted. But once the beams were exposed to 700degC, the mechanical properties and bond performance of the beams greatly deteriorated lowering the effectiveness of CFRP to a great extent. In notched specimens, CFRP played a partial role in delaying failure, but was incapable of damaging the material due to intermediate crack-induced debonding around the high-stress regions. Strain analysis showed that, with the proper use of surface preparation methods, CFRP could change the failure mode to that of interfacial debonding to cohesive failure in the adhesive layer. The yielding moment capacity which is being predicted has an average theoretical/experimental ratio of 0.98 and 12.8% coefficient of variation (COV). and the maximum moment capacity being predicted has an average theoretical/experimental ratio of 1.01 and a coefficient of variation (COV) of 7.2%. Verifying the validity of the suggested method of assessment of post-fire structures.
Monkij et al. (Fri,) studied this question.