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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。
Thick fireproof coating was used to test the temperature-rise and fire-resistance performance under three conditions of ISO834, including three CFRP shear-strengthened RC beams and one comparison beam. The temperature distribution of the test beam with time was obtained. The influence of different loading methods, shear span ratio, reinforcement amount and thickness of fire protection layer on the failure morphology and fire resistance of CFRP shear-strengthened beams under high temperature was analyzed. Experimental results show that the shear span ratio is the main factor that affects the fire resistance and failure modes of CFRP shear-strengthened beams under high temperature. The thickness of shear-strengthened fire-retardant coating can increase the fire-resistance limit of shear failure but does not change the fire-resistance limit of bending failure. The program of calculating the temperature field of the cross-section of carbon fiber shear-strengthened concrete beam with thick fire protection coating was developed. The correctness of the program was verified by the test results. This study supplements the factors that affect the fire resistance of reinforced concrete beams strengthened by carbon fiber shear under high temperature.