摘要
本文对碳纤维布(CFRP)加固钢筋混凝土箱形梁在不同的扭剪比作用下进行抗扭性能的试验研究。根据不同的扭剪比(即0.958、1.597和2.556)将12片钢筋混凝土箱梁分为3组,每组中3片梁采用不同的CFRP加固方式,如U形条带加固和U形条带+纵向条带加固。试验结果表明,在极限荷载作用下,所有梁其裂缝的开裂角与扭剪比成正比,但当扭剪比为0.958时接近纯剪破坏下裂缝角度的45°角。试验中出现两种破坏模式:"CBS"中U形条带和部分"CBSL"在主裂缝处剥落和"1CBSL2"中纵向条带断裂,纵向条带对于箱梁的极限扭矩的提高具有一定的作用。对于加固效果,2层U形条带+纵向条带的粘压,使得加固梁的抗扭性能有最大限度的提升,其抗扭提高量:3CBSL2为76.2%,1CBSL2为55.2%,2CBSL2为46.9%,抗扭的提高量与扭剪比成反比,但对于仅采用U形条带加固的箱梁其抗扭承载力提高量最小,U形条带对箱梁的加固效果未能有显著的增强。从总的趋势来看扭转角与扭剪比成正比,扭剪比的增大使抗扭强度的增加量降低,其扭转角峰值却在增加,而抗扭强度并没有与扭转角成一定比例的关系。
In this paper,the torsional behavior of CFRP reinforced concrete box beams under different torque-to-shear ratios were investigated in the experimental study.According to different torque-to-shear ratios(ie,0.958,1.597,and 2.556),12 reinforced concrete box beams were divided into 3 groups,and 3 beams in each group were strengthened by CFRP with different configurations,such as U-shaped strips and U-shaped strips with longitudinal strips.The test results showed that at the ultimate load the cracking angles of all beams were proportional to the torque-to-shear ratios.But,when the torque-to-shear ratio was 0.958,the angle of cracks was close to the 45°angle of the crack angle under pure shear failure.Besides,two failure modes appeared in the experiment:U-shaped strips peeled off and the longitudinal strips ruptured,which shows the longitudinal strips compressed the U-shaped stripes to contribute the torsional strength for the"CBSL"series strengthened beams.Moreover,the improvements of torque of the beams presenting 76.2%for 3 CBSL2,55.2%for 1 CBSL2,and 46.9%for 2 CBSL which shows increase in torsional resistance was inversely proportional to the torque-to-shear ratio.For beams strengthened with only U-shaped strips,however,the torsional capacity was increased moderately,due to the U-shaped strips which have not significantly enhanced the reinforcement effect of the box girder.Therefore,the torsional behavior and strengthening effectiveness of the strengthened beams is affected by the CFRP configuration and the torque-to-shear ratio.
作者
马生强
孙鉴峰
MA Sheng-qiang;SUN Jian-feng(College of Architectural and Civil Engineering,Xinjiang University,Urumqi 830047,China)
出处
《复合材料科学与工程》
CAS
北大核心
2020年第9期29-36,共8页
Composites Science and Engineering
基金
中央高校基金重点科研平台开放基金项目(CHD300102219525)。
关键词
钢筋混凝土箱梁
碳纤维布
加固方式
扭剪比
抗扭性能
复合材料
reinforced concrete box beam
carbon fiber reinforced polymer
strengthening pattern
torque-to-shear ratio
torsional behavior
composites
