1、ACI 440.2R-08Reported by ACI Committee 440Guide for the Design and Constructionof Externally Bonded FRP Systemsfor Strengthening Concrete StructuresGuide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete StructuresEighth printingErrata as of 02/27/15ISBN 978
2、-0-87031-285-4Copyright by the American Concrete Institute, Farmington Hills, MI. All rights reserved. This materialmay not be reproduced or copied, in whole or part, in any printed, mechanical, electronic, film, or otherdistribution and storage media, without the written consent of ACI.The technica
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11、0.2R-08 supersedes ACI 440.2R-02 and was adopted and published July 2008.Copyright 2008, 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, pri
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15、 contract documents, theyshall be restated in mandatory language for incorporation bythe Architect/Engineer.Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete StructuresReported by ACI Committee 440Fiber-reinforced polymer (FRP) systems for strengthenin
16、g concrete structuresare an alternative to traditional strengthening techniques, such as steelplate bonding, section enlargement, and external post-tensioning. FRPstrengthening systems use FRP composite materials as supplementalexternally bonded reinforcement. FRP systems offer advantages overtradit
17、ional strengthening techniques: they are lightweight, relatively easyto install, and are noncorrosive. Due to the characteristics of FRP materials aswell as the behavior of members strengthened with FRP, specific guidanceon the use of these systems is needed. This document offers general infor-matio
18、n on the history and use of FRP strengthening systems; a descriptionof the unique material properties of FRP; and committee recommendationson the engineering, construction, and inspection of FRP systems used tostrengthen concrete structures. The proposed guidelines are based on theknowledge gained f
19、rom experimental research, analytical work, and fieldapplications of FRP systems used to strengthen concrete structures.Keywords: aramid fibers; bridges; buildings; carbon fibers; concrete;corrosion; crack widths; cracking; cyclic loading; deflection; developmentlength; earthquake-resistant; fatigue
20、; fiber-reinforced polymers; flexure;shear; stress; structural analysis; structural design; torsion.CONTENTSPART 1GENERALChapter 1Introduction and scope, p. 31.1IntroductionTarek Alkhrdaji*Russell Gentry James G. Korff Andrea ProtaCharles E. Bakis Janos Gergely Michael W. Lee Hayder A. RasheedLawren
21、ce C. Bank William J. Gold Maria Lopez de Murphy Sami H. RizkallaAbdeldjelil Belarbi Nabil F. Grace Ibrahim M. Mahfouz Morris SchupackBrahim Benmokrane Mark F. Green Orange S. Marshall Rajan SenLuke A. Bisby Zareh B. Gregorian Amir Mirmiran Khaled A. Soudki*Gregg J. Blaszak Doug D. Gremel Ayman S. M
22、osallam Samuel A. Steere, IIITimothy E. Bradberry Shawn P. Gross John J. Myers Gamil S. TadrosGordon L. Brown, Jr. H. R. Trey Hamilton, III Antonio Nanni Jay ThomasVicki L. Brown Issam E. Harik Kenneth Neale Houssam A. ToutanjiRaafat El-Hacha Kent A. Harries John P. Newhook J. Gustavo TumialanGarth
23、J. Fallis Mark P. Henderson Ayman M. Okeil Milan VatovecAmir Z. Fam Bohdan N. Horeczko Carlos E. Ospina Stephanie WalkupEdward R. Fyfe Vistasp M. Karbhari Max L. Porter David White*Co-chairs of the subcommittee that prepared this document.The Committee also thanks Associate Members Joaquim Barros, H
24、akim Bouadi, Nestore Galati, Kenneth Neale, Owen Rosenboom, Baolin Wan, in addition to Tom Harmon,Renata Kotznia, Silvia Rocca, and Subu Subramanien for their contributions.John P. BuselChairCarol K. ShieldSecretaryACI 440.2R-082 DESIGN AND CONSTRUCTION OF EXTERNALLY BONDED FRP SYSTEMS (ACI 440.2R-0
25、8)American Concrete Institute Copyrighted Materialwww.concrete.org1.2Scope and limitations1.3Applications and use1.4Use of FRP systemsChapter 2Notation and definitions, p. 52.1Notation2.2Definitions and acronymsChapter 3Background information, p. 103.1Historical development3.2Commercially available
26、externally bonded FRPsystemsPART 2MATERIALSChapter 4Constituent materials and properties,p. 114.1Constituent materials4.2Physical properties4.3Mechanical properties4.4Time-dependent behavior4.5Durability4.6FRP systems qualificationPART 3RECOMMENDED CONSTRUCTION REQUIREMENTSChapter 5Shipping, storage
27、, and handling, p. 155.1Shipping5.2Storage5.3HandlingChapter 6Installation, p. 166.1Contractor competency6.2Temperature, humidity, and moisture considerations6.3Equipment6.4Substrate repair and surface preparation6.5Mixing of resins6.6Application of FRP systems6.7Alignment of FRP materials6.8Multipl
28、e plies and lap splices6.9Curing of resins6.10Temporary protectionChapter 7Inspection, evaluation, and acceptance,p. 197.1Inspection7.2Evaluation and acceptanceChapter 8Maintenance and repair, p. 218.1General8.2Inspection and assessment8.3Repair of strengthening system8.4Repair of surface coatingPAR
29、T 4DESIGN RECOMMENDATIONSChapter 9General design considerations, p. 219.1Design philosophy9.2Strengthening limits9.3Selection of FRP systems9.4Design material propertiesChapter 10Flexural strengthening, p. 2410.1Nominal strength10.2Reinforced concrete members10.3Prestressed concrete membersChapter 1
30、1Shear strengthening, p. 3211.1General considerations11.2Wrapping schemes11.3Nominal shear strength11.4FRP contribution to shear strengthChapter 12Strengthening of members subjected to axial force or combined axial and bending forces, p. 3412.1Pure axial compression12.2Combined axial compression and
31、 bending12.3Ductility enhancement12.4Pure axial tensionChapter 13FRP reinforcement details,p. 3713.1Bond and delamination13.2Detailing of laps and splices13.3Bond of near-surface-mounted systemsChapter 14Drawings, specifications, and submittals, p. 4014.1Engineering requirements14.2Drawings and spec
32、ifications14.3SubmittalsPART 5DESIGN EXAMPLESChapter 15Design examples, p. 4115.1Calculation of FRP system tensile properties15.2Comparison of FRP systems tensile properties15.3Flexural strengthening of an interior reinforcedconcrete beam with FRP laminates15.4Flexural strengthening of an interior r
33、einforcedconcrete beam with NSM FRP bars15.5Flexural strengthening of an interior prestressedconcrete beam with FRP laminates15.6Shear strengthening of an interior T-beam15.7Shear strengthening of an exterior column15.8Strengthening of a noncircular concrete column foraxial load increase15.9Strength
34、ening of a noncircular concrete column forincrease in axial and bending forcesChapter 16References, p. 6616.1Referenced standards and reports16.2Cited referencesAPPENDIXESAppendix AMaterial properties of carbon, glass, and aramid fibers, p. 72Appendix BSummary of standard test methods,p. 73DESIGN AN
35、D CONSTRUCTION OF EXTERNALLY BONDED FRP SYSTEMS (ACI 440.2R-08) 3American Concrete Institute Copyrighted Materialwww.concrete.orgAppendix CAreas of future research, p. 74Appendix DMethodology for computation of simplified P-M interaction diagram for noncircular columns, p. 75PART 1GENERALCHAPTER 1IN
36、TRODUCTION AND SCOPE1.1IntroductionThe strengthening or retrofitting of existing concretestructures to resist higher design loads, correct strength lossdue to deterioration, correct design or construction deficiencies,or increase ductility has traditionally been accomplishedusing conventional materi
37、als and construction techniques.Externally bonded steel plates, steel or concrete jackets, andexternal post-tensioning are just some of the many traditionaltechniques available.Composite materials made of fibers in a polymeric resin,also known as fiber-reinforced polymers (FRPs), haveemerged as an a
38、lternative to traditional materials for repair andrehabilitation. For the purposes of this document, an FRPsystem is defined as the fibers and resins used to create thecomposite laminate, all applicable resins used to bond it to theconcrete substrate, and all applied coatings used to protect thecons
39、tituent materials. Coatings used exclusively for aestheticreasons are not considered part of an FRP system.FRP materials are lightweight, noncorrosive, and exhibithigh tensile strength. These materials are readily available inseveral forms, ranging from factory-made laminates to dryfiber sheets that
40、 can be wrapped to conform to the geometryof a structure before adding the polymer resin. The relativelythin profiles of cured FRP systems are often desirable inapplications where aesthetics or access is a concern.The growing interest in FRP systems for strengthening andretrofitting can be attribute
41、d to many factors. Although thefibers and resins used in FRP systems are relatively expensivecompared with traditional strengthening materials such asconcrete and steel, labor and equipment costs to install FRPsystems are often lower (Nanni 1999). FRP systems can alsobe used in areas with limited ac
42、cess where traditionaltechniques would be difficult to implement.The basis for this document is the knowledge gained froma comprehensive review of experimental research, analyticalwork, and field applications of FRP strengthening systems.Areas where further research is needed are highlighted inthis
43、document and compiled in Appendix C.1.2Scope and limitationsThis document provides guidance for the selection, design,and installation of FRP systems for externally strengtheningconcrete structures. Information on material properties,design, installation, quality control, and maintenance of FRPsyste
44、ms used as external reinforcement is presented. Thisinformation can be used to select an FRP system for increasingthe strength and stiffness of reinforced concrete beams or theductility of columns and other applications.A significant body of research serves as the basis for thisdocument. This resear
45、ch, conducted over the past 25 years,includes analytical studies, experimental work, and monitoredfield applications of FRP strengthening systems. Based onthe available research, the design procedures outlined in thisdocument are considered to be conservative. It is important tospecifically point ou
46、t the areas of the document that stillrequire research.The durability and long-term performance of FRP materialshas been the subject of much research; however, this researchremains ongoing. The design guidelines in this document doaccount for environmental degradation and long-termdurability by sugg
47、esting reduction factors for variousenvironments. Long-term fatigue and creep are alsoaddressed by stress limitations indicated in this document.These factors and limitations are considered conservative. Asmore research becomes available, however, these factors willbe modified, and the specific envi
48、ronmental conditions andloading conditions to which they should apply will be betterdefined. Additionally, the coupling effect of environmentalconditions and loading conditions still requires further study.Caution is advised in applications where the FRP system issubjected simultaneously to extreme
49、environmental andstress conditions. The factors associated with the long-termdurability of the FRP system may also affect the tensilemodulus of elasticity of the material used for design.Many issues regarding bond of the FRP system to thesubstrate remain the focus of a great deal of research. Forboth flexural and shear strengthening, there are manydifferent varieties of debonding failure that can govern thestrength of an FRP-strengthened member. While most of thedebonding modes have been identifi
