ACI 440.7R-2010 Guide for the Design and Construction of Externally Bonded Fiber-Reinforced Polymer Systems for Strengthening Unreinforced Masonry Structures《加固无钢筋砌体结构外贴纤维增强聚合体系统的设.pdf

1、ACI 440.7R-10Reported by ACI Committee 440Guide for the Design andConstruction of Externally BondedFiber-Reinforced Polymer Systemsfor Strengthening UnreinforcedMasonry StructuresEmerging Technology SeriesGuide for the Design and Construction of Externally Bonded Fiber-Reinforced Polymer Systems for

2、 Strengthening Unreinforced Masonry StructuresFirst PrintingApril 2010ISBN 978-0-87031-373-8American Concrete InstituteAdvancing concrete knowledgeCopyright by the American Concrete Institute, Farmington Hills, MI. All rights reserved. This materialmay not be reproduced or copied, in whole or part,

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11、 Concrete Institute38800 Country Club DriveFarmington Hills, MI 48331U.S.A.Phone: 248-848-3700Fax: 248-848-3701www.concrete.orgACI 440.7R-10 was adopted and published April 2010.Copyright 2010, American Concrete Institute.All rights reserved including rights of reproduction and use in any form or by

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13、etors.440.7R-1ACI Committee Reports, Guides, Manuals, and Commentariesare intended for guidance in planning, designing, executing,and inspecting construction. This document is intended for theuse of individuals who are competent to evaluate thesignificance and limitations of its content and recommen

14、dationsand who will accept responsibility for the application of thematerial it contains. The American Concrete Institute disclaimsany and all responsibility for the stated principles. The Instituteshall not be liable for any loss or damage arising therefrom.Reference to this document shall not be m

15、ade 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 language for incorporation bythe Architect/Engineer.Guide for the Design and Construction of Externally Bonded Fiber-Reinforced Po

16、lymer Systems for Strengthening Unreinforced Masonry StructuresReported by ACI Committee 440Fiber-reinforced polymer (FRP) systems are an option to consider forstrengthening unreinforced masonry (URM) structures. Traditionalstrengthening systems include external steel plates, reinforced concrete(RC)

17、 overlays, span shortening with steel subframing or bracing, andinternal steel reinforcement. Relative to traditional systems, features ofFRP systems include high tensile strength, light weight, ease of construction,and resistance to corrosion. This guide offers general information on FRPsystems use

18、, a description of their unique material properties, and recom-mendations for the design, construction, and inspection of FRP systems forstrengthening URM structures. These guidelines are based on knowledgegained from a comprehensive review of experimental and analytical inves-tigations and field ap

19、plications.Keywords: buildings; cracking; cyclic loading; detailing; earthquakeresistance; fiber-reinforced polymers; fibers; flexure; masonry; shear;structural analysis;structural design; unreinforced.Tarek Alkhrdaji Amir Z. Fam Maria Lopez de Murphy Sami H. RizkallaCharles E. Bakis William J. Gold

20、 Ibrahim M. Mahfouz Morris SchupackLawrence C. Bank Nabil F. Grace Orange S. Marshall Rajan SenAbdeldjelil Belarbi Mark F. Green Amir Mirmiram Khaled A. SoudkiBrahim Benmokrane Zareh B. Gregorian John J. Myers Samuel A. Steere IIILuke A. Bisby Doug D. Gremel Antonio Nanni Gamil S. TadrosGregg J. Bla

21、szak Shawn P. Gross John P. Newhook Jay ThomasHakim Bouadi H. R. Trey Hamilton III Ayman M. Okeil Houssam A. ToutanjiTimothy E. Bradberry Issam E. Harik Carlos E. Ospina J. Gustavo TumialanVicki L. Brown Kent A. Harries Renato Parretti Milan VatovecGordon L. Brown Jr. Mark P. Henderson Max L. Porter

22、 David WhiteRaafat El-Hacha Bohdan N. Horeczko Andrea Prota*Sarah E. WittGarth J. Fallis Michael W. Lee Hayder A. Rasheed*Chair of the subcommittee that prepared this report.The committee acknowledges the significant contributions of Associate Members Nestore Galati and Rudi Seracino. The committee

23、also thanks the members of TheMasonry Society (TMS) Existing Masonry Committee for their help in reviewing this document.John P. BuselChairCarol K. ShieldSecretaryACI 440.7R-10Emerging Technology SeriesACI encourages the development and appropriate use of new and emerging technologies through the pu

24、blication of the Emerging TechnologySeries. This series presents information and recommendations based on available test data, technical reports, limited experience with fieldapplications, and the opinions of committee members. The presented information and recommendations, and their basis, may be l

25、ess fullydeveloped and tested than those for more mature technologies. This report identifies areas in which information is believed to be less fullydeveloped, and describes research needs. The professional using this document should understand the limitations of this document and exercisejudgment a

26、s to the appropriate application of this emerging technology.440.7R-2 ACI COMMITTEE REPORTCONTENTSChapter 1Introduction and scope, p. 440.7R-21.1Introduction1.2ScopeChapter 2Notation and definitions, p. 440.7R-32.1Notation2.2DefinitionsChapter 3Constituent materials and properties,p. 440.7R-63.1Cons

27、tituent materials3.2Physical properties3.3Mechanical properties3.4Time-dependent behavior3.5Durability3.6Fiber-reinforced polymer system qualificationChapter 4Shipping, storage, and handling,p. 440.7R-94.1Shipping4.2Storage4.3HandlingChapter 5Installation, p. 440.7R-105.1Contractor competency5.2Temp

28、erature, humidity, and moisture considerations5.3Equipment5.4Substrate repair and surface preparation5.5Resin mixing5.6Application of constituent materials5.7Alignment of FRP materials5.8Multiple plies and lap splice5.9Resins curing5.10Temporary protectionChapter 6Inspection, evaluation, and accepta

29、nce, p. 440.7R-126.1Inspection6.2Evaluation and acceptanceChapter 7Maintenance and repair, p. 440.7R-147.1General7.2Inspection and assessment7.3Repair of strengthening system7.4Repair of surface coatingChapter 8General design considerations,p. 440.7R-148.1Design philosophy8.2Strengthening limits8.3D

30、esign material properties8.4Effective strain and stress in the FRP reinforcementat the strength limit stateChapter 9Wall strength for out-of-plane-loads,p. 440.7R-169.1Background information9.2General considerations9.3Existing wall strength9.4Nominal flexural strength of FRP-reinforced masonrywalls

31、subjected to out-of-plane loads9.5Serviceability9.6Creep rupture stress limitsChapter 10Wall strengthening for in-plane-loads, p. 440.7R-2010.1Background information10.2General considerations10.3Existing wall strength10.4Nominal shear strength of FRP-reinforced masonrywalls subjected to in-plane loa

32、ds10.5Nominal flexural strength of FRP-reinforced wallssubjected to in-plane loads10.6Wall strengthening for shear and flexureChapter 11Detailing, p. 440.7R-2511.1General requirements11.2Fiber-reinforced polymer debonding11.3Spacing limits11.4Anchorages of FRP reinforcement11.5Alternate forms of anc

33、horing11.6Load path continuityChapter 12Drawings, specifications, and submittals, p. 440.7R-2812.1Engineering requirements12.2Drawings and specifications12.3SubmittalsChapter 13Design examples, p. 440.7R-2913.1Increasing the flexural capacity of a wall subjectedto out-of-plane loads13.2Increasing th

34、e lateral capacity of a wall subjected toin-plane loadsChapter 14References, p. 440.7R-4314.1Referenced standards and reports14.2Cited referencesCHAPTER 1INTRODUCTION AND SCOPE1.1IntroductionMasonry is a generic term used to describe a type ofconstruction where clay, or concrete masonry units, ornat

35、ural stones are bonded together to form a load-bearingstructure or a component in a structure. Non-load-bearingmasonry includes partitions and veneers.Although masonry is used in flexural applications such asretaining walls, roof and floor beams, and lintels, it is morefrequently used in load-bearin

36、g walls primarily resistingcompression loads. Reinforced and unreinforced masonry(URM) walls have been used in constructing structural load-bearing components. In buildings, masonry walls can serveeffectively as part of the lateral load-resisting system toresist wind and earthquake loads. Infill mas

37、onry walls play asignificant role in enhancing in-plane stiffness and shearresistance of both reinforced concrete (RC) and steel frames,if properly connected to the structural frame.EXTERNALLY BONDED FRP SYSTEMS FOR STRENGTHENING UNREINFORCED MASONRY STRUCTURES 440.7R-3Unreinforced masonry structure

38、s have shown theirvulnerability to major events such as earthquakes, severewind, blast, and impact. In addition, factors such as changein occupancy, deterioration, or an increase in lateral-loaddemand, may create the need to perform structural retrofit.ACI 530 covers the design and construction of n

39、ew masonry;the repair, retrofitting, and rehabilitation of masonry struc-tures are not included in that code.The repair and retrofit/rehabilitation of existing masonrystructures have traditionally been accomplished usingconventional materials and construction techniques. Externallybonded steel plate

40、s, RC overlays, grouted cell reinforcements,and post-tensioning are just some of the many traditionaltechniques available. Fiber-reinforced polymer (FRP) (ACI440R) composites have emerged as an alternative to traditionalmaterials for strengthening masonry structures. Fiber-reinforced polymer materia

41、ls are lightweight and noncorrosive.They exhibit high tensile strength and elastic modulus(carbon FRP), and are impact resistant with electromagnetictransparency. These materials, which are available in avariety of forms, including flat sheets and plates and reinforcingbars and prestressing tendons

42、of typically round crosssection, provide the licensed design professional with flexibilityin achieving desired performance. Fiber-reinforced polymersystems can be used in seismic, wind, or blast strengtheningof URM structural elements.Advantages of retrofitting masonry using FRP compositesinclude ea

43、sier handling and installation with resulting lowerinstallation prices, and minimal changes to the structuresappearance. Disturbance to occupants and loss of usablespace are also minimized. Dynamic properties of the existingstructure remain unchanged because there is little weightaddition or stiffne

44、ss modification. Disadvantages of usingFRP may include diminished performance at elevated temper-atures, requirement for protective coatings, degradation ofmechanical properties after long-term exposure to certainenvironmental conditions such as extensive moisture intrusionand frequent wet freezing-

45、and-thawing cycles, and the rela-tively higher level of site supervision and inspection required.1.2ScopeThis guideline provides information on the selection anddesign of FRP systems limited to externally bonded FRPlaminates and near-surface-mounted FRP bars/strips forincreasing the in-plane and out

46、-of-plane strength of existingungrouted, grouted, or partially grouted URM walls; infillwalls are not included in this guide. The guide is applicableto URM structures made of clay bricks, concrete masonryunits, and natural stones using conventional types of mortar.For masonry with significant deteri

47、oration, questionablemortar bond, and cracking and/or element displacement,traditional procedures may be required as well as FRP strength-ening. The evaluation for the need to apply traditional modesof strengthening is not covered in this guide.CHAPTER 2NOTATION AND DEFINITIONSACI provides a compreh

48、ensive list of notation and definitionsthrough an online resource, “ACI Concrete Terminology,”http:/terminology.concrete.org. Definitions provided hereincomplement that resource.2.1NotationAf= cross-sectional area of FRP reinforcement, in.2(mm2)Af,bar= area of one rectangular and/or circular FRP bar

49、,in.2(mm2)An= area of net mortared/grouted section, in.2(mm2)ab= smallest dimension of a FRP rectangular bar, in.(mm)bb= largest dimension of a FRP rectangular bar, in. (mm)CE= environmental reduction factorc = distance from the fiber of maximum compressivestrain to the neutral axis, in. (mm)cs= distance from the fiber of maximum compressivestrain to the neutral axis at service limit state, in.(mm)D = dead load effectdb= diameter of a FRP bar, in. (mm)df= effective depth of FRP flexural reinforcement, in.(mm)di=