This paper presents experimental and numerical investigations on the fire behaviour of reinforced concrete (RC) beams and slabs flexurally strengthened with carbon fibre reinforced polymer (CFRP) laminates. The first part of this paper summarizes the main results obtained from fire resistance tests on loaded CFRP-strengthened RC beams with fire protection systems, which included relatively thin layers of calcium silicate boards or vermiculite/perlite cement based mortar applied along the bottom soffit of the beams; in addition, the anchorage zones of the CFRP laminates were highly thermally insulated and this constructive detail allowed extending considerably the fire endurance of the CFRP strengthening systems. The numerical study, described in the second part of this paper, included the development of (i) 2D finite element (FE) models of the tested beams, which were validated based on the agreement between calculated temperatures and those measured in the tests; and (ii) 3D FE models of CFRP-strengthened RC slabs, which were used to assess the efficacy of different fire protection system configurations, with particular relevance being given to the geometry of the thermal insulation applied at the anchorage zones.
Keywords: reinforced concrete; strengthening systems; carbon fibre reinforced polymer (CFRP) laminates; fire; anchorage zones; protection systems.
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