外贴碳纤维布加固大比例钢筋混凝土梁抗弯性能  

Flexural behavior of large-scale RC beams reinforced with externally bonded carbon fiber sheets

作　　者：周朝阳[1] 李毅卉[1] 贺学军[1] 

机构地区：[1]中南大学土木建筑学院,湖南长沙410075

出　　处：《铁道科学与工程学报》2007年第4期41-46,共6页Journal of Railway Science and Engineering

基　　金：铁道部科技计划项目(2002G043);教育部博士点基金资助项目(20050533042)

摘　　要：以某类铁路桥梁为原型,通过5根粘贴碳纤维布加固钢筋混凝土梁的1/3比例模型试验,研究了梁表面处理方式和加固前预载历史对加固梁抗弯能力和破坏形态的影响。试验结果表明,粘贴表面打磨的梁发生纤维布带面层剥离破坏,而凿毛处理时最终破坏均为混凝土压碎;若不出现剥离破坏,则碳纤维布具有良好的加固效果;加固时,梁上既有荷载越小,则加固效果越好。基于《规程》(CECS146:2003)的基本假定,考虑既有荷载的影响,对本文试件的屈服弯矩和极限弯矩进行理论分析,其结果与实测值较吻合,说明《规程》中计算屈服后压碎时的的正截面承载力公式对碳纤维布加固较大尺度、较高配筋混凝土梁也是适用的。With a type of railway bridge as a prototype, five one - third - scale specimens of reinforced concrete beams were made, and four of them were strengthened with externally bonded carbon fiber sheets. The parametere investigated in this study included the way of treating concrete surface and the level of pre - loading at strengthening. Their effects on the flexural capacity and failure mode were particularly considered. The experimental results show that the ultimate failure is characterized by concrete crushing when the beam surface is roughened by picking. In contrast, peelingoff happens in case of surface planing. Externally bonded CFRP sheets can increase the flexural capacity of the beam significantly if debonding is avoided. In addition, the results indicate that the lighter the pre - load on the beam, the more the increment of its ultimate load compared to that of unstrengthened specimen. In consideration of the influence of pre - load, theoretical analyses are carried out to predict the bending moments at rebar yielding and concrete crushing on the basis of the assumptions from the specification （CECS146： 2003）. The calculated resuhs are in good agreement with the measured values for referred members. Meanwhile design algorithm of the corresponding capacity in the specification is validated for CFRP sheet - strengthened concrete beams with rather large sizes of section and heavy ratiopercentage of steel reinforcement.

关 键 词：外贴 碳纤维布 抗弯加固 钢筋混凝土梁 

分 类 号：U448.34[建筑科学—桥梁与隧道工程]