In order to study the effect of carbon fiber reinforced polymer(CFRP)reinforced concrete in the negative moment zone on the fire resistance of composite beams,a numerical model of CFRP sheets reinforced composite beams under fire was established.By analysing the mid-span deflection of the combined beam,the stresses of the concrete in the negative moment zone and the cross-section bending moment with the temperature,the effects of the bond width,length and load ratio of the CFRP sheets on the fire resistance of the combined beam were investigated.The results show that,the bonding of CFRP sheets effectively slows down the development of tensile stress in concrete,the end of the CFRP sheets and the longitudinal edges produce high interfacial stress,and debonding occurs when it reaches the ultimate bond stress.The increase of the bonding width of the CFRP sheets improves the load carrying capacity of the composite girder,and prevents debonding from occurring.The optimum width of bonding is 200 mm.The bonding length is less than 1 600 mm,the fire resistance performance increases with the increase of bonding length,and when it is greater than 1 600 mm,it does not contribute much to the fire resistance performance.
steel-concrete composite beamreinforced with CFRP sheetsnegative moment zonefire resistance
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