CFRP抗剪加固钢筋混凝土梁的耐火性能试验研究

Experiments Study on Fire Resistance of CFRP Shear Strengthened Reinforced Concrete Beam

采用厚型防火涂料对4根碳纤维布抗剪加固钢筋混凝土梁和1根对比梁进行了ISO834标准升温条件下的恒载升温耐火性能试验,得到了试验梁的测点温度、位移随时间增加的分布关系。分析了不同加载方式、剪跨比、加固量和防火保护层厚度对高温下CFRP抗剪加固梁的跨中挠度、破坏形态及耐火极限的影响。试验结果表明:在相同的弯、剪富余量,相等加固量条件下,高温下剪切破坏的耐火极限小于弯曲破坏的耐火极限;抗剪加固防火涂料的厚度可以提高剪切破坏的耐火极限,但不改变弯曲破坏的耐火极限;抗剪加固梁剪切破坏的跨中挠度近似为弯曲破坏的一半。试验结论补充了高温下CFRP加固构件的研究成果。

Fire-resistance performance experiments with static loading-fire are investigated about four CFRP shear strengthened and one without CFRP strengthened reinforced concrete（RC） beams exposed to the ISO834 standard fire.Shear strengthened RC beams are wrapped with fire insulation material-thick painted fire retardant coatings.Relationships between measure points temperature,displacement and time are achieved.The effects of different load mode,shear-span ratio,strength ratio and fire insulation thickness on the mid-span deflection,failure mode and fire-resistance rating of the shear strengthened RC beams are investigated.The results suggest that： With the same redundant bend or shear capacity,strengthening ratio,fire resistance of bend failure than shear failure;not bending-failure fire-resistance rating,but shear-failure fire-resistance rating is increased by thickening fire insulation to shear strengthened RC beams;mid-span deflection of shear failure is approximate one half of bending failure when shear strengthened RC beams.The experiment results give a supplement to research of CFRP strengthened structural members in fire.