碳纤维布抗弯加固钢筋混凝土梁的耐火性能试验研究

通过一根未加固钢筋混凝土梁，以及五根碳纤维布抗弯加固钢筋混凝土梁的三面受火试验，探讨不同厚度的厚涂型防火涂料、不同荷载比、不同碳纤维布加固量等因素对碳纤维布抗弯加固钢筋混凝土梁耐火性能的影响。结果表明：高温下该类构件的破坏形态大致可分为受弯破坏和弯剪破坏两类，常温下发生弯曲破坏的加固构件有可能在高温下出现破坏形态的转变；虽然加固构件所承受的荷载明显大于未加固构件，前者由于防火涂料的保护，其耐火极限仍大于后者。只要科学合理地设置防火保护层，碳纤维布抗弯加固钢筋混凝土梁的耐火性能完全能够满足实际工程需要。

Experimental Study on Fire Resistance of Reinforced Concrete Beams Strengthened in Flexure with Carbon Fiber Sheets

Based on the fire tests of one unstrengthened reinforced concrete beam and five reinforced concrete beams strengthened in flexure with carbon fiber sheets, the influence of fire insulation thickness, load ratio and strengthening ratio on the fire resistance of reinforced concrete beam strengthened in flexure with carbon fiber sheet has been discussed. The experimental results show that: (a) the failure mode of strengthened beam at elevated temperature can be classified as flexure failure mode or flexure-shear failure mode, and the failure mode of strengthened beam at high temperature may be different from that at room temperature; and (b) although the load supported by the strengthened specimen is larger than that supported by the unstrengthened specimen, the fire resistance of the strengthened specimen is still larger than that of the unstrengthened specimen, due to the influence of fire insulation. Fire performance of reinforced concrete beam strengthened in flexure with carbon fiber sheets can satisfy the need of practical engineering as long as the fire insulation is set reasonably.