Evaluation of Thermal Resistance of FRP Reinforced Concrete Beams in Fire

Abstract

Fibre reinforced polymer (FRP) bars are made of innovative materials and establishment of the fire resistance of FRP reinforced concrete (RC) is necessary for their widespread application. Experimental behaviours of Carbon FRP (CFRP) and Glass FRP (GFRP) bar RC beams at elevated temperatures have been investigated in this paper. Data are presented from fire tests of six simply supported beams that were fabricated using normal-weight concrete. The effects of varying load levels and FRP bar type were studied. The beams were designed over-reinforced and were tested in a floor furnace. A steel bar reinforced beam was used as control specimen. A rebar temperature of 500°C was selected as failure criterion for the beam. Non-linear temperature distribution across the beam cross section was observed. Temperature rise in the compression concrete was found insignificant and its mechanical properties were nearly unaffected. All beams met the failure criterion of critical rebar temperature of 500°C. The stiffness reduction in the GFRP and steel RC beams was nearly the same at elevated temperatures and was independent of load levels and/or bar modulus. The CFRP bar reinforced beams showed better stiffness characteristics compared to other beams.