1、ACI ITG-5.1-07Acceptance Criteria for SpecialUnbonded Post-TensionedPrecast Structural Walls Based onValidation Testing and CommentaryReported by ACI Innovation Task Group 5An ACI StandardAmerican Concrete InstituteAdvancing concrete knowledgeAcceptance Criteria for Special Unbonded Post-Tensioned P
2、recast Structural WallsBased on Validation Testing and CommentaryFirst printingMarch 2008ISBN 978-0-87031-270-0Copyright 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, electron
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4、nd information or requirements that may be subject to more than one interpretation or may beincomplete or incorrect. Users who have suggestions for the improvement of ACI documents arerequested to contact ACI. Proper use of this document includes periodically checking for errata atwww.concrete.org/c
5、ommittees/errata.asp for the most up-to-date revisions.ACI committee documents are intended for the use of individuals who are competent to evaluate thesignificance and limitations of its content and recommendations and who will accept responsibility for theapplication of the material it contains. I
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10、ts are available in print, by download, on CD-ROM, through electronicsubscription, or reprint and may be obtained by contacting ACI.Most ACI standards and committee reports are gathered together in the annually revised ACI Manual ofConcrete Practice (MCP).American Concrete Institute38800 Country Clu
11、b DriveFarmington Hills, MI 48331U.S.A.Phone: 248-848-3700Fax: 248-848-3701www.concrete.orgACI ITG-5.1-07 was adopted October 24, 2007 and published March 2008.Copyright 2008, American Concrete Institute.All rights reserved including rights of reproduction and use in any form or by anymeans, includi
12、ng the making of copies by any photo process, or by electronic ormechanical device, printed, written, or oral, or recording for sound or visual reproductionor for use in any knowledge or retrieval system or device, unless permission in writingis obtained from the copyright proprietors.ITG-5.1-1ACI C
13、ommittee Reports, Guides, Manuals, StandardPractices, and Commentaries are intended for guidance inplanning, designing, executing, and inspecting construction.This document is intended for the use of individuals who arecompetent to evaluate the significance and limitations of itscontent and recommen
14、dations and who will acceptresponsibility for the application of the material it contains.The American Concrete Institute disclaims any and allresponsibility for the stated principles. The Institute shall notbe 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.Acceptance Criteria for Special UnbondedPost-Tensioned Precast Structural Wall
16、sBased on Validation Testing and CommentaryAn ACI StandardReported by ACI Innovation Task Group 5ACI ITG-5.1-07This document applies to structures in regions of high seismic risk or tostructures assigned to high seismic performance or design categories. Itdefines the minimum experimental evidence th
17、at can be deemed to satisfythe use of unbonded post-tensioned precast structural walls (shear walls)for bearing wall and building frame special reinforced concrete shear wallsystems, as defined in ASCE/SEI 7-05, when those walls do not fully satisfythe intent of the prescriptive requirements of Chap
18、ter 21 of ACI 318-05.This document includes mandatory Acceptance Criteria and nonmandatoryCommentary, and has been written in such a form that its requirements canbe coordinated directly with the requirements for special precast structuralwalls in 21.8 of ACI 318-05. Among the subjects covered are r
19、equirementsfor the procedures that shall be used to design unbonded post-tensionedprecast test modules and their configurations, as well as requirements fortesting, reporting, and assessing satisfactory performance of the test modules.The references of the Commentary provide documentary evidence,add
20、itional to the references of Chapter 21 of ACI 318R-05, that support theacceptance criteria. Consistent with the approach of ACI 318, no comparisonis made, either in the body of the Acceptance Criteria or Commentary, ofresearch results for precast test modules satisfying ACI 318 with those formodule
21、s that, although not satisfying ACI 318, do satisfy the AcceptanceCriteria. Such comparisons, both experimental and analytical, are available inthe Commentary references.In this document, consistent with the format of ACI 318-05, the word“Section” is not included before a reference to a section of A
22、CI 318-05. Tomore clearly designate a section in this document, however, the word“Section” is used before any reference to a section of this document.The section numbering for the Commentary is the same as that for theStandard, with numbers preceded by an “R” and the text in italics to distin-guish
23、them from the corresponding section numbers of the Standard.Keywords: acceptance criteria; coupling element; drift; drift angle;energy dissipation; lateral resistance; post-tensioning; precast concrete;prestressed concrete; seismic design; shear wall; structural wall; testmodule; toughness.CONTENTSC
24、hapter 1Introduction and scope, p. ITG-5.1-2Chapter 2Notation and definitions, p. ITG-5.1-5Chapter 3Design procedure, p. ITG-5.1-8Chapter 4Test modules, p. ITG-5.1-9Chapter 5Test method, p. ITG-5.1-12Chapter 6Test report, p. ITG-5.1-15Chapter 7Test module acceptance criteria,p. ITG-5.1-16Chapter 8Re
25、ferenced standards, p. ITG-5.1-18Attila B. Beres Vilas S. Mujumdar Carol K. ShieldNed M. Cleland Suzanne Dow Nakaki John W. WallaceNeil M. Hawkins Stephen P. Pessiki Loring A. Wyllie, Jr.Ronald KlemencicConsulting memberS. K. GhoshCharles W. DolanChairITG-5.1-2 ACI STANDARDCHAPTER 1INTRODUCTION AND
26、SCOPE1.1IntroductionFor seismic design, 21.2.1.5 of ACI 318 specifies that “areinforced concrete structural system not satisfying therequirements of this chapter (Chapter 21) shall be permittedif it is demonstrated by experimental evidence and analysisthat the proposed system has strength and toughn
27、ess equal toor exceeding those provided by a comparable monolithicreinforced concrete structure satisfying this chapter.” Thisdocument defines the minimum experimental evidencerequired to validate the use of special unbonded post-tensioned precast structural wall systems in regions of highseismic ri
28、sk or for structures assigned to high seismicperformance or design categories when those systems do notsatisfy fully the prescriptive requirements of Chapter 21 ofACI 318. The provisions of this document are intended tosupplement the provisions of Chapter 21 of ACI 318 and notto supplant them.Consis
29、tent with the 21.2.1.5 requirement of ACI 318, thisdocument specifies that, before the validation testingmandated by the document is undertaken, a design procedureshall have been developed for prototype unbonded post-tensioned precast structural walls having the generic formfor which acceptance is s
30、ought. Further, the same designprocedure shall be used to proportion the test modules. Thedocument also requires that the prototype buildings thatcontain the unbonded post-tensioned precast structural wallshave proportions that are essentially regular in the verticaldirection, having no significant
31、physical discontinuities inplan, in vertical configuration, or in their lateral-force-resistingsystems.This document is intended for walls that might, forexample, involve the use of precast elements, precast/prestressed elements, post-tensioned reinforcement or combi-nations of those elements and re
32、inforcement. Comprehensiveprescriptive requirements for unbonded post-tensionedprecast structural walls constructed with such elements arenot included in ACI 318.1.2Scope and general requirementsR1.2Scope and general requirementsWhile only ACI Committee 318 can specify the requirementsnecessary for
33、unbonded post-tensioned precast walls to meetthe provisions of 21.2.1.5 of ACI 318, 1.4 of ACI 318 permitsthe building official to accept precast wall systems, otherthan those explicitly covered by Chapter 21 of ACI 318,provided specific tests, load factors, deflection limits,construction procedures
34、, and other pertinent requirementshave been established for acceptance of such systemsconsistent with the intent of the Code. This documentprovides a framework that establishes the specific tests, loadfactors, deflection limits, and other pertinent requirementsappropriate for acceptance for regions
35、of high seismic riskor for structures assigned to high seismic performance ordesign categories of unbonded post-tensioned precast wallsystems, including unbonded post-tensioned precast coupledwall systems, not satisfying all the prescriptive requirementsof Chapter 21 of ACI 318.This document assumes
36、 that the unbonded post-tensionedprecast wall system to be tested has details that differ fromthose prescribed by 21.7 of ACI 318 for conventionalmonolithic reinforced concrete construction. Such wallsmay, for example, involve the use of precast elements,precast prestressed elements, post-tensioned
37、reinforcement,or combinations of those elements and reinforcement. Lifesafety and toughness are theoretically enhanced by mildsteel reinforcement grouted across the wall to foundationinterface. The presence of mild steel reinforcement,however, makes erection more difficult, and may inhibit theself-c
38、entering action provided by unbonded post-tensioningcrossing the same interface. For an uncoupled wall, mildsteel reinforcement, or some other form of energy-dissipatingbase connection, is necessary to meet the relative energydissipation requirements of this document. For coupledwalls, however, ener
39、gy-dissipating coupling elements can beused along the vertical boundaries between walls so thatonly unbonded post-tensioning tendons need to cross thewall to foundation interface. Life safety for coupled walls isthen more critically dependent on the unbonded post-tensioning not fracturing under the
40、seismic event. In thatcase, careful attention should be paid to corrosion protection ofthe tendon and to stress increases in the tendon during theseismic event.For monolithic reinforced concrete walls, a fundamentaldesign concept underlying the Chapter 21 provisions of ACI318 is that walls with hw/l
41、w exceeding 1.0 should beproportioned so that their inelastic response is dominated byflexural action on a critical section located near the base ofthe wall. That same basic fundamental concept is retained inthis document. The limiting hw/lwvalue, however, is reducedto 0.5. The basis for that lower
42、limit is discussed in R1.2.2.Tests on modules, as envisioned in this document, cannotbe extrapolated with confidence to the performance ofpanelized walls of proportions differing from those tested forthe development of Chapter 21 of ACI 318 if the shear-slipdisplacement pattern or excessive joint op
43、ening pattern ofFig. R2.3 is significant in the response developed in the teston the module.Two other fundamental requirements of Chapter 21 of ACI318 are for closely spaced ties around heavily strainedboundary element reinforcement and the provision ofminimum amounts of uniformly distributed horizo
44、ntal andvertical reinforcement in the web of the wall. Ties aroundboundary element reinforcement to inhibit its buckling incompression are required where the strain in the extremecompression fiber exceeds 0.003 and spalling of the coverconcrete may occur. Those ties then provide confinementthat main
45、tains the integrity of the boundary element andpermits the confined concrete to develop increasingcompressive forces with increasing lateral displacements inspite of the loss of the concrete cover. Minimum amounts ofuniformly distributed horizontal and vertical reinforcementover the height and lengt
46、h of the wall are required to restrainthe opening of inclined cracks and allow the development ofSPECIAL UNBONDED POST-TENSIONED PRECAST STRUCTURAL WALLS ITG-5.1-3the minimum acceptable drift angle capacities specified inSection 5.4. Deviations from those tie and distributedreinforcement requirement
47、s are possible only if a theory isdeveloped that can substantiate reasons for such deviationsand that theory is tested as part of the validation testing.1.2.1 This document defines minimum acceptance criteriafor unbonded post-tensioned precast structural walls,including coupled unbonded post-tension
48、ed precast structuralwalls, designed for regions of high seismic risk or for structuresassigned to high seismic performance or design categories,where acceptance is based on experimental evidence andanalysis.R1.2.1 This document is not intended for use directly withexisting construction or for use w
49、ith walls that are designedto conform to all the requirements of 21.7 of ACI 318. Thecriteria of this document are at least as stringent as those forwalls designed to the minimum requirements of 21.7 of ACI318. Some walls designed to 21.7, and having low height-length ratios, may not meet the minimum acceptable driftangle capacity of Eq. (5-1) because their behavior may begoverned almost entirely by shear deformations (Hidalgo etal. 2002). The height-length ratio of 0.5 is the least value forwhich Eq. (5-1) is applicable.1.2.2 This document is applicable to unbonded post-tension
