摘要
碳纤维布加固混凝土结构是一种新型的结构加固方法。本文主要研究了碳纤维布对钢筋混凝土T梁的抗剪加固。以五片T梁模型破坏试验为基础，研究了碳纤维布粘贴层数及方式和二次受力对钢筋混凝土T梁抗剪极限承载力的影响规律。试验结果表明，粘贴碳纤维布显著减小了钢筋混凝土T梁的裂缝数量和宽度，抑制了裂缝的开展，对提高普通钢筋混凝土构件耐久性有重要作用；采用适当的锚固措施可以有效防止构件发生早期破坏，提高构件的极限抗剪能力；对于有锚固的粘贴方式，有预加载的T梁抗剪极限承载力明显高于无预加载的T梁。试验还表明，在无锚固的情况下，用碳纤维布作抗剪加固后的T梁破坏较突然，有可能使梁的加固效果出现负效应。在结果分析中，应用非线性有限元分析程序，采用混凝土块单元、接触分析及单元“死活”等分析方法对试验梁进行全过程分析，给出了一种碳纤维布加固RC梁的数值研究方法。基于桁架理论，引用有效粘贴长度的概念，以粘贴层所能承受的极限抗力为计算控制参数，提出了碳纤维布对钢筋混凝土T梁极限承载力及正常使用阶段的加固计算方法。本文还简要介绍了碳纤维布粘贴效果的分析方法，以及用于碳纤维布抗剪加固的几种锚固措施。
本文为进一步研究碳纤维布对钢筋混凝土T梁桥加固及数值分析方法研究奠定了理论基础，同时也为桥梁加固实践提供了设计计算与试验依据。
The rehabilitation of reinforced concrete structures with CFRP laminates is a new reinforcement technique. In this paper, shear capacity of existing RC T-section beams using CFRP composites is discussed. Based on the experiments of five models of RC T-section beams, the ultimate shear capacity of RC T-section beams strengthened with different number of plies, paste formats and initial loads is evaluated. From the experiments, the number and width of fracture are obviously decreased, and pasting CFRP laminates play important role in improving RC construction durability; with anchoring, premature is prevented and the ultimate shear capacity is increased; taking properly anchoring measure, the ultimate shear capacity of RC T-section beams of initial loads is higher than that of no initial loads; under non-anchoring case, because the rehabilitation of RC T-section beams with CFRP laminates are destroyed suddenly, the reinforcement effect maybe decrease. According to the experimental result, the nonlinear finite element software which offers contact analysis, concrete mass element and the birth and death capabilities is used in the whole procedures of analysis and new numerical analyzing method of shear capacity of existing RC T-section beams using CFRP composites is included. In theory research based on truss theory, the effective length of the CFRP sheet and ultimate capacity of paste layer is introduced, then the calculation procedure of the ultimate shear capacity of RC T-section beams strengthened with CFRP laminates is put forward, so did the reinforcement design method of normal service phase. In this paper, analytic methods of paste effect of CFRP laminates and several sort of anchor measurement are introduced.
This paper has set a foundation for bridge strengthening with CFRP laminates and numerical analysis in future and provides reference for design and examination in bridge strengthening practice.
引文
[1]中华人民共和国交通部标准．公路钢筋混凝土及预应力混凝土桥涵设计规范(JTJ023-55)。
[2]吴智深．FRP复合材料在基础工程设施的增强和加固方面的现状与发展．中国首届纤维增强塑料(FRP)混凝土结构学术交流会论文集，2000年6月
[3]叶列平、谭壮．纤维增强塑料混凝土在土木工程中的应用综述．中国首届纤维增强塑料(FRP)混凝土结构学术交流会论文集，2000年6月
[4]陈瑜．用碳纤维布加固混凝土构件时的粘贴构造与锚固．中国首届纤维增强塑料(FRP)混凝土结构学术交流会论文集，2000年6月
[5]吴刚、安琳、吕志涛．碳纤维布用于钢筋混凝土梁抗剪加固的试验研究分析，中国首届纤维增强塑料(FRP)混凝土结构学术交流会论文集，2000年6月
[6]过镇海．钢筋混凝土原理．清华大学出版社，1999年
[7]邵容光．结构设计原理．人民交通出版社，1987
[8]袁旭斌．碳纤维布对RC梁抗弯加固研究．[研究生论文]．西安．长安大学，2002
[9]Miller,B.and Nanni,A. "Bond Between CFRP Sheets and concrete," Proceedings, ASCE 5th Materials Congress,Cincinnati, OH,L.C.Bank, Editor, May 10-12,1999.pp 240-247
[10]Khalifa, A., T.Alkhrdaji, A.Nanni, and S.Lansburg, "Anchorage of surface Mounted FRP Reinforcement," Concrete International: Design and construction, Vol.21, No.10, Oct.1999,pp.49-54.
[11]K.Brosens and D.Van Gemert "Strengthening of Concrete Structures with Externally Bonded Steel Plates or CFRP Laminates-Partl:Specific Design Concepts" repair and maintenance of reinforced concrete structures Tonji university, shanghai.October 2001,195-232
[12].Khalifa, A. and A. Nanni "Improving Shear Capacity of Existing RC T-Section Beams Using CFRP Composites,. Cement and Concrete Composites, Vol.22, No.2, July2000, pp. 165-174.
[13]贾应春、蔡登山．纤维加劲复合板与混凝土的粘贴效应．世界桥梁，2003年第3期
[14]肖建庄、李杰、魏锦涛．纤维布与混凝土之间粘结力的试验方法研究．玻璃钢／复合材料，2003．No．3
[15]张继文等．外部粘贴碳纤维或钢板加固梁中粘贴界面应力分析．东南大学学报，Vol．32 No．5 sept．2002
[16]贺拴海，宋一凡，彭多善 粘贴钢板加固钢筋混凝土梁式桥的分析研究，西安公路交通大学学报，Vol．20 No．2Apr．2000
[17]上海加固行．碳纤维材料技术手册，2001
[18]Taketo Uomoto, Hiroshi Mutsuyoshi, etc.Use of Fiber Reinforced Polymer Composites as Reinforcing Material for Concrete. JOURNAL OF MATERIALS IN CIVIL ENGINEERING/MAY/JUNE 2002
[19]Yang, X., and A. Nanni, "Concrete Beams Strengthened with Misaligned CFRP Laminates," Non-Metallic Reinforcement for Concrete Structures- FRPRCS-5, Cambridge, July 16-18, 2001, pp. 79-85
[20]Brosens.Kris and Van Gemert. Dionys,(1997) "Anchoring stresses between concrete and Carbon Fibre Reinforced Laminates", Proceeding of the Third International symposium on Non-Metallic(FRP)Reinforcement for Concrete structures,Vol.1 Japan Concrete Institute, Japan, 271-278
[21]Damian Kachlakev, PhD etc, FINITE ELEMENT MODELING OF REINFORCED CONCRETE STRUCTURES STRENGTHENED WITH FRP LAMINATES Final Report. May 2001
[22]非线性分析程序Ansys使用手册
[23]刘涛、杨凤鹏．精通Ansys．清华大学出版社，2002年
[24]Chansawat, K., "Nonlinear Finite Element Analysis of Reinforced Concrete Structure Strengthened With FRP Laminates," personal communications, Corvallis, Oregon, 2000.
[25]Horiguchi, Takashi and Saeki, Noboru, (1997)..Effect of Test Methods and Quality of Concrete on Bond Strength of CFRP Sheet,. Proceedings of the Third International Symposium on Non-Metallic (FRP) Reinforcement for Concrete Structures, Vol 1, Japan Concrete Institute, Japan, pp. 265-270.