低预应力碳纤维布加固混凝土梁桥的关键技术研究

发布时间：2018-01-03 23:05

本文关键词：低预应力碳纤维布加固混凝土梁桥的关键技术研究　出处：《河北工业大学》2014年硕士论文　论文类型：学位论文

【摘要】：目前，碳纤维布加固方法凭借其优点，受到了国内众多学者的青睐。普通碳纤维加固方法存在许多弊端且不能充分发挥碳纤维的高抗拉性能，因此众多学者提出了预应力碳纤维布加固，此加固方法在桥梁领域的研究已经取得部分成果，但由于张拉设备的限制，造成预应力碳纤维加固的实际应用性比较差，将预应力碳纤维加固应用到实际工程中的比较少。本文遵循实用性和易操作性，在预应力碳纤维布加固的基础上提出低预应力碳纤维加固方法。推导了低预应力加固方法的理论计算方法，并采用体外筋反拱法对12根矩形截面简直梁进行了静载试验。研究了加载历史、预应力水平对加固效果的影响，验证了理论分析结果的正确性。通过静载试验研究得出了一下结论： 1)无应力CFRP布加固构件未能提高构件的极限承载能力，加载前期CFRP不发挥作用，，存在应力滞后现象。屈服荷载以后能抑制裂缝的发展，最终的破坏形式为剥离破坏； 2)本文低应力加固CFRP布初始应变达到75810-6加固效果最佳，预应力CFRP布加固极限承载力可提高44%~61%，提高了构件的屈服荷载，有效的抑制了裂缝的开展。 3)低应力加固构件的刚度有所提高，加载前期裂缝几乎不发展，提高了构件的开裂荷载，减小了挠度的增长速度。 4)低应力加固构件的延性很接近原构件，能保证加固构件有很好的变形能力。 5)本试验低应力加固构件的CFRP初始应变达到55110-6时，构件的破坏形式为CFRP被拉断，屈服荷载以后无明显破坏征兆，属于脆性破坏。 6)验证了低应力碳纤维布加固桥梁碳纤维布上所加预应力公式推导的正确性。
[Abstract]:At present, the carbon fiber cloth reinforcement method with its advantages, by many domestic scholars of all ages. There are many shortcomings and can not give full play to the high tensile properties of carbon fiber reinforcement method of carbon fiber, so many scholars put forward the prestressed CFRP reinforcement method, this research in the field of bridge has achieved some results, but because tension device limitations caused by application of prestressed carbon fiber reinforcement is relatively poor, the prestressed carbon fiber reinforcement applied to the actual project is relatively small.
This paper follows the practicability and maneuverability, the reinforcement method of low prestressed carbon fiber based on Prestressed CFRP reinforcement method is deduced. The low stress theoretical calculation method, and the in vitro anti rib arch method of 12 rectangular cross-section beam's static load experiment is carried out. On the loading history, prestress level on strengthening effect, verify the results of theoretical analysis. Through the static load test of draw the conclusion:
1) no stress CFRP cloth reinforcement component failed to improve the ultimate bearing capacity of the component. CFRP did not play a role in the early stage of loading. There was a stress hysteresis phenomenon. After yielding load, the development of cracks could be inhibited, and the final failure form was peeling failure.
2) in this paper, the initial strain of CFRP cloth strengthened with low stress reaches 75810-6, and the effect of reinforcement is the best. The ultimate bearing capacity of prestressed CFRP fabric can increase 44%~61%, increase the yield load of components, and effectively restrain the development of cracks.
3) the stiffness of the component with low stress is improved, and the crack is almost not developed at the early stage of loading. The cracking load of the component is improved and the growth rate of the deflection is reduced.
4) the ductility of the low stress reinforced component is very close to the original component, and it can guarantee the good deformation ability of the reinforced component.
5) in the test, when the initial strain of CFRP is 55110-6, the failure mode of the component is CFRP, which is broken. No obvious damage symptom is observed after yielding load. It belongs to brittle failure.
6) the correctness of the derivation of the prestress formula of the carbon fiber cloth reinforced bridge with low stress carbon fiber cloth was verified.

【学位授予单位】：河北工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U445.72

【参考文献】