EXPERIMENTAL STUDY ON PRESTRESSED CFRP FLEXURAL METHOD OF RC BEAM BASED ON EARLY WARNING THEORY
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摘要: 针对预应力碳纤维增强复材(CFRP)加固后构件的延性明显降低、安全储备不足、破坏前没有明显预兆问题,提出基于预警理论的预应力CFRP抗弯加固设计方法。该方法在加固构件的实际安全储备低于设计的目标值时可以通过自身预警保险丝的断裂发出明显的预警信号。为研究该设计方法加固后的构件破坏前是否可以发出明显的预警信号、通过定义合理的构件屈服点后安全储备是否可以满足设计要求,制作了4根混凝土梁并进行抗弯性能试验。试验结果表明:加固构件在安全储备低于设计值时保险丝断裂、剥离发出预警信号;通过最远法与作图法确定的构件屈服点与预警点一致,通过采用基本安全指标和等效安全指标评估,以预警点作为加固构件的屈服点相较于以钢筋屈服作为构件屈服点更加合理且安全储备满足要求。Abstract: Aiming at the problem that the ductility of the prestressed CFRP strengthened members is obviously reduced, the safety reserve is insufficient, and there is no obvious omen before the damage, a prestressed CFRP bending reinforcement design method based on early warning theory was proposed. In this method, a clear early warning signal can be given by the break of the self-warning fuse when the actual safety reserve of the reinforcing member is lower than the designed target value. In order to study whether the component after reinforcement by using the design method can emit a clear early warning signal and whether the safety reserve can meet design requirements by defining reasonable yield point of components, four reinforced concrete beams were produced and tested for bending resistance. The test results showed that, when the safety reserve was lower than the design value, the fuse was detached from the beam after the fuse fractured, and an early warning signal was issued; the yield point of the component determined by the farthest method and the mapping method was consistent with the warning point. After evaluation by K0 and Keq, the yield point of the pre-warning point as the reinforcing member was more reasonable than the traditional method, and the safety reserve of the components could meet the requirements.
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