CFS抗剪加固钢筋混凝土梁的耐火性能研究

采用厚型防火涂料对3根碳纤维布抗剪加固钢筋混凝土梁和1根对比梁进行ISO834标准升温条件下的恒载升温耐火性能试验,得到试验梁的测点温度随时间增加的分布关系。分析不同加载方式、剪跨比、加固量和防火保护层厚度对高温下CFRP抗剪加固梁的破坏形态及耐火极限的影响。试验研究表明:剪跨比是高温下影响CFRP抗剪加固梁耐火极限和破坏形态的主要因素;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。编制了设有厚型防火涂料保护的碳纤维抗剪加固混凝土梁的截面温度场计算程序,通过试验结果验证程序的正确性。为全面考虑影响高温下碳纤维抗剪加固钢筋混凝土梁耐火极限的因素提供补充。

Experimental and Numerical Researches on Fire Resistance of CFS Shear Strengthened Reinforced Concrete Beams

Fire-resistance performance experiments with static loading-fire are investigated about three CFS shear strengthened and one without CFS 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. Relationship between measure points temperature and time are achieved. The effects of different load mode, shear-span ratio, strength ratio and fire insulation thickness on the failure mode and fire-resistance rating of the shear strengthened RC beams are investigated. The results suggest that: the ratio of shear-span is the main factor to fire-resistance rating and failure modes of CFS shear strengthened RC beams in fire; not bending-failure fire-resistance rating, but shear-failure fire-resistance rating are increased by thickening fire insulation to shear strengthened RC beams. A computer program is developed to calculate the temperature fields of fire insulated concrete beams shear strengthened with carbon fiber sheet (CFS) coated thick fireproof material. This program is validated comparing with experimental results. Researches can give a supplement to produce overall fire-resistance factors of CFS shear strengthened reinforced concrete beams at high temperatures.