预应力芳纶纤维布加固混凝土梁的受弯性能研究

本文对预应力芳纶纤维布加固钢筋混凝土梁的受弯性能做了初步的研究,并提出了带永久锚具的预应力芳纶纤维布加固混凝土梁的施工工艺。通过10根试件的受弯试验,对比了预应力芳纶纤维布加固的混凝土梁与非预应力芳纶纤维布加固的混凝土梁的开裂弯矩、屈服弯矩、极限弯矩及抗弯刚度等工作性能,分析了芳纶纤维布的预应力水平和加固层数对试件受弯性能的影响。试验结果表明,非预应力芳纶纤维布加固的试验梁与未加固的基准梁相比,其开裂弯矩提高了12%~16%,屈服弯矩提高了13%~29%,极限弯矩提高了26%~65%;预应力芳纶纤维布加固的试验梁与未加固的基准梁相比,其开裂弯矩提高了114%~306%,屈服弯矩提高了38%~101%,极限弯矩提高了29%~101%。可见,预应力芳纶纤维布能显著地提高被加固钢筋混凝土梁的受弯性能。在试验研究基础上,本文给出了承载力计算方法,计算结果与实测值符合较好。

Study on flexural performance of RC beams strengthened with prestressed AFRP sheets

In this paper,a preliminary study on flexural performance of strengthening RC beams is carried out,in which prestressed aramid fiber reinforced plastic(AFRP) sheets with permanent anchor and its construction technology of strengthening and prestressing are used.Based on the experimental study of ten specimens,the beams strengthened with prestressed AFRP sheets are compared with the beams strengthened with un-prestressed AFRP sheets on the properties of cracking moment,yield moment,ultimate moment and flexural stiffness.In addition,the effects of different prestress level and number of layers of AFRP sheets on these behavior are discussed.The experimental results show that,comparison between the beams strengthened with un-prestressed AFRP sheets and the un-strengthened beams,the cracking moment increases by 12% to 16%,the yield moment increases from 13% to 29% and the ultimate moment increases from 26% to 65%.Comparison between the beams strengthened with prestressed AFRP sheets and the un-strengthened beams,the cracking moment increases from 114% to 306%,the yield moment increases from 38% to 101% and the ultimate moment increases from 29% to 101%,validating the efficiency of prestressed AFRP sheet retrofit.Finally,the formulas for computing the load-carrying capacity of the strengthening beams are established.The results from the formulas generally agree with those from the experiment.