1、ACI 440.4R-04(Reapproved 2011)Prestressing Concrete Structureswith FRP TendonsReported by ACI Committee 440Emerging Technology SeriesISBN 978-0-87031-166-6Prestressing Concrete Structures with FRP TendonsFirst PrintingDecember 2004American Concrete InstituteAdvancing concrete knowledgeCopyright by t
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10、ng ACI.Most ACI standards and committee reports are gathered together in the annually revised ACI Manual ofConcrete Practice (MCP).American Concrete Institute38800 Country Club DriveFarmington Hills, MI 48331U.S.A.Phone: 248-848-3700Fax: 248-848-3701www.concrete.orgACI 440.4R-04 became effective Sep
11、tember 21, 2004.Copyright 2004, American Concrete Institute.All rights reserved including rights of reproduction and use in any form or by anymeans, including the making of copies by any photo process, or by electronic ormechanical device, printed, written, or oral, or recording for sound or visual
12、reproduc-tion or for use in any knowledge or retrieval system or device, unless permission inwriting is obtained from the copyright proprietors.1ACI Committee Reports, Guides, Manuals, and Commentariesare intended for guidance in planning, designing, executing,and inspecting construction. This docum
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14、ted principles. The Instituteshall not be liable for any loss or damage arising therefrom.Reference to this document shall not be made in contractdocuments. If items found in this document are desired by theArchitect/Engineer to be a part of the contract documents, theyshall be restated in mandatory
15、 language for incorporation bythe Architect/Engineer.Tarek Alkhrdaji Edward R. Fyfe Vistasp M. Karbhari Morris SchupackCharles E. Bakis Ali Ganjehlou James G. Korff David W. ScottP. N. Balaguru Duane J. Gee Michael W. Lee Rajan SenLawrence C. Bank T. Russell Gentry John Levar Mohsen A. ShahawyAbdeld
16、jelil Belarbi Janos Gergely Ibrahim Mahfouz Carol K. ShieldBrahim Benmokrane William J. Gold Henry N. Marsh Khaled A. SoudkiGregg J. Blaszak Nabil F. Grace Orange S. Marshall Robert E. SteffenTimothy E. Bradberry Mark F. Green Amir Mirmiran Gamil TadrosGordon L. Brown Mark Greenwood Ayman S. Mosalla
17、m Jay ThomasVicki L. Brown Doug D. Gremel Antonio Nanni Houssam A. ToutanjiThomas I. Campbell*H. R. Hamilton Kenneth Neale Miroslav VadovicCharles W. Dolan*Issam E. Harik John P. Newhook David VanderpoolDat Duthinh Kent A. Harries Max L. Porter Milan VatovecGarth J. Fallis Mark P. Henderson Mark A.
18、Postma David WhiteAmir Fam Bohdan Horeczko Hayder A. Rasheed*Co-chairs of Subcommittee 440-I.Note: The committee acknowledges the significant contribution of associate member Raafat El-Hacha.Prestressing Concrete Structures with FRP TendonsReported by ACI Committee 440ACI 440.4R-04(Reapproved 2011)E
19、merging Technology SeriesFiber-reinforced polymers (FRPs) have been proposed for use instead ofsteel prestressing tendons in concrete structures. The promise of FRP materialslies in their high-strength, lightweight, noncorrosive, nonconducting, andnonmagnetic properties. This document offers general
20、 information on thehistory and use of FRP for prestressing applications and a description ofthe material properties of FRP. The document focuses on the current stateof design, development, and research needed to characterize and ensure theperformance of FRP as prestressing reinforcement in concrete
21、structures. TheSami H. RizkallaChairJohn P. BuselSecretaryACI encourages the development and appropriate use of new and emerging technologies through the publication of the Emerging TechnologySeries. This series presents information and recommendations based on available test data, technical reports
22、, limited experience with fieldapplications, and the opinions of committee members. The presented information and recommendations, and their basis, may be less fullydeveloped and tested than those for more mature technologies. This report identifies areas in which information is believed to be less
23、fullydeveloped, and describes research needs. The professional using this document should understand the limitations of this document andexercise judgment as to the appropriate application of this emerging technology.proposed guidelines are based on the knowledge gained from worldwideexperimental re
24、search, analytical work, and field applications of FRPsused as prestressed reinforcement. The current development includes abasic understanding of flexure and axial prestressed members, FRP shearreinforcement, bond of FRP tendons, and unbonded or external FRP tendonsfor prestressing applications. Th
25、e document concludes with a description ofresearch needs.Keywords: anchorage; bond length; crack; deflection; deformation; developmentlength; ductility; fatigue; jacking stresses; post-tensioning; prestressed con-crete; pretensioning; reinforcement ratio; shear; tendon.CONTENTSChapter 1Introduction,
26、 p. 21.1Organization and limitations of document1.2Historical development and use of FRP reinforcement1.3Design guidelines and technical committees2 PRESTRESSING CONCRETE STRUCTURES WITH FRP TENDONS (ACI 440.4R-04)American Concrete Institute Copyrighted Materialwww.concrete.org1.4Research efforts1.5
27、Demonstrations and field applications1.6Definitions1.7NotationChapter 2FRP tendons and anchorages, p. 92.1FRP tendon characterization2.2Commercial tendons2.3Description of tendons2.4Anchorage characterizationChapter 3Flexural design, p. 133.1General considerations3.2Strength design methodology3.3Bal
28、anced ratio3.4Flexural design and capacity prediction3.5Strength reduction factors for flexure3.6Flexural service stresses3.7Jacking stresses3.8Creep rupture of FRP tendons3.9Correction of stress for harped tendons3.10Relaxation and friction losses3.11Overall design approach3.12Ductility or deformab
29、ility3.13Minimum reinforcementChapter 4Serviceability, p. 204.1General4.2Deflection4.3Crack width and spacing4.4FatigueChapter 5Shear, p. 215.1General considerations in design of FRP stirrups5.2Shear strength with FRP stirrups5.3Spacing limits for shear reinforcement5.4Minimum amount of shear reinfo
30、rcement5.5Detailing of shear stirrupsChapter 6Bond and development, p. 236.1Introduction6.2Transfer length6.3Flexural bond length6.4Design considerationsChapter 7Unbonded and external tendon systems, p. 257.1Unbonded prestressed members7.2External prestressingChapter 8Pile driving and in-place flexu
31、re, p. 278.1General8.2Demonstration studies8.3Discussion8.4ConclusionsChapter 9Research needs, p. 29Chapter 10References, p. 3010.1Referenced standards and reports10.2Cited referencesAppendix ADesign example, p. 34CHAPTER 1INTRODUCTIONFiber-reinforced polymer (FRP) composites have beenproposed for u
32、se as prestressing tendons in concrete structures.The promise of FRP materials lies in their high-strength,lightweight, noncorrosive, nonconducting, and nonmagneticproperties. In addition, FRP manufacturing, using variouscross-sectional shapes and material combinations, offersunique opportunities fo
33、r the development of shapes andforms that would be difficult or impossible with conventionalsteel materials. Lighter-weight materials and preassembly ofcomplex shapes can boost constructibility and efficiency ofconstruction. At present, the higher cost of FRP materialssuggests that FRP use will be c
34、onfined to applicationswhere the unique characteristics of the material are mostappropriate. Efficiencies in construction and reduction infabrication costs will expand their potential market. FRPreinforcement is available in the form of bars, grids, plates,and tendons. This document examines both in
35、ternal andexternal prestressed reinforcement in the form of tendons.One of the principal advantages of FRP tendons forprestressing is the ability to configure the reinforcement tomeet specific performance and design objectives. FRPtendons may be configured as rods, bars, and strands asshown in Fig.
36、1.1. The surface texture of FRP tendons mayvary, resulting in bond with the surrounding concrete thatvaries from one tendon configuration to another. Unlikeconventional steel reinforcement, there are no standardizedshapes, surface configurations, fiber orientation, constituentmaterials, and proporti
37、ons for the final products. Similarly, thereis no standardization of the methods of production, such aspultrusion, braiding, filament winding, or FRP preparation for aspecific application. Thus, FRP materials require considerableengineering effort to use properly. Bakis (1993) has outlinedmanufactur
38、ing processes.FRP tendons are typically made from one of three basicfibers. These fibers are aramid, carbon, and glass. Aramidfibers consist of a semicrystalline polymer known asaromatic polyamide. Carbon fibers are based on the layeredgraphene (hexagonal) networks present in graphite, whileglass ge
39、nerally uses either E-glass or S-glass fibers. E-glassis a low-cost calcium-aluminoborosilicate glass used wherestrength, low conductivity, and acid resistance are important.S-glass is a magnesium-aluminosilicate glass that has higherstrength, stiffness, and ultimate strain than E-glass. S-glasscost
40、s more than E-glass, and both are susceptible todegradation in alkaline environments. Table 1.1 givesproperties of typical fibers.The selection of the fiber is primarily based on considerationof cost, strength, stiffness, and long-term stability. Withinthese fiber groups, different performance and m
41、aterialcharacteristics may be achieved. For example, aramids maycome in low, high, and very high modulus configurations.Carbon fibers are also available with moduli ranging frombelow that of steel to several multiples of that of steel. Of theseveral fiber types, glass-based FRP reinforcement is leas
42、texpensive and generally uses either E-glass or S-glass fibers.PRESTRESSING CONCRETE STRUCTURES WITH FRP TENDONS (ACI 440.4R-04) 3American Concrete Institute Copyrighted Materialwww.concrete.orgThe resins used for fiber impregnation are usually thermo-setting and may be polyester, vinylester, epoxy,
43、 phenolic, orpolyurethane. The formulation, grade, and physical-chemicalcharacteristics of resins are practically limitless. The possiblecombinations of fibers, resins, additives, and fillers makegeneralization of the properties of FRP tendons very difficult.Additionally, FRP composites are heteroge
44、neous andanisotropic. Final characteristics of an FRP tendon are dependenton fiber and resin properties, as well as the manufacturingprocess. Specific details of a particular tendon should beobtained from the manufacturer of the tendon.1.1Organization and limitations of documentThe emphasis of this
45、document is on flexural members inconcrete buildings and bridges pretensioned with aramid orcarbon FRP tendons. An FRP prestressing system consists ofthe tendon and the anchorage. Properties, performance, andoverall behavior are dependent on the tendon/anchoragesystem and on the individual component
46、s. Performance ofindependent elements should be verified by test. Informationis provided for bonded and unbonded post-tensionedapplications where it is available. Only fully prestressedmembers are considered, with no attempt being made toaddress partially prestressed members. In general, to accountf
47、or the brittle characteristics of FRP, unlike steel, which isductile, the recommendations herein are conservative. Specificlimitations of FRP tendons are addressed and research needsare listed in Chapter 9. The committee feels that this documentis relevant to simple spans and to spans made continuou
48、s byplacing steel reinforcement in the deck of a bridge structure.No recommendations are made for beams made continuouswith FRP tendons or for moment-resisting frames whereductility or large deformations are required for seismic loading.The worldwide number of prestressed FRP applications is lesstha
49、n 100 (MDA 2004; IABSE 2003). Most are bridge structureswhere issues of fire were not considered critical.1.2Historical development and use of FRP reinforcementThe concept of using short glass fiber reinforcement inconcrete was first introduced in the 1930s but was not developedinto long fiber reinforcement for nearly two decades. In the1950s and 1960s, the U.S. Army Corps of Engineers wassufficiently interested in long glass fibers for reinforcementthat a series of comprehensive reports was compiled (Matherand Tye 1955; Pepper an
