碳纤维布加固的钢筋砼吊车梁的抗弯疲劳性能

为研究碳纤维布(CFRP)对加固后钢筋混凝土梁的抗弯疲劳性能的影响,进行了三根CFRP加固梁及一根对比梁的抗弯疲劳试验。研究了碳纤维布加固方式、构件使用荷载等参数对碳纤维布加固钢筋混凝土吊车梁抗弯疲劳性能的影响。试验研究表明:采用碳纤维布加固后,构件裂缝的宽度减小了50.2%~66%,发展速度也得到控制,钢筋应力减小24.1%~28.2%,构件的刚度提高14.9%~16.1%。依据试验结果,从现有规范中关于构件刚度计算以及寿命分析的方法出发,进行了CFRP加固钢筋混凝土吊车梁的疲劳刚度、寿命的计算分析,理论分析结果表明,用这种方法计算得到的结果可以满足工程上对精度的要求。最后以试验结果为基础,对CFRP加固梁的疲劳设计提出了合理化建议。

Bending fatigue behavior of RC crane beam strengthened with carbon fiber reinforced plastic

To understand the fatigue behavior of damaged RC beams strengthened with CFRP, three T-shaped beams strengthened with CFRP and one contrast beam were tested. The effects of the strengthening mode and the load level on the bending fatigue behavior of the beams were investigated. Experiment results show that, with CFRP strengthening, the width of the crack is reduced by 50.2% -66%, and the development of the crack are eased, the stress of the reinforcing steel bar is reduced by 24.1% - 28. 2%, and the stiffness of the beam is raised by 14. 9% - 16. 1%. Based on the results, an accurate model of the stiffness calculation and the S-N curves are obtained. The model and the S-N curves can be used as references in engineering practice. Suggestions on the fatigue design of CFRP strengthened beams are given.