1、ACI ITG-4.3R-07Reported by ACI Innovation Task Group 4and Other ContributorsReport on Structural Design andDetailing for High-Strength Concrete inModerate to High Seismic ApplicationsReport on Structural Design and Detailing for High-Strength Concretein Moderate to High Seismic ApplicationsFirst Pri
2、ntingSeptember 2007ISBN 978-0-87031-254-0American 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, in any printed, mechanical, electronic, film, or ot
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11、on Hills, MI 48331U.S.A.Phone: 248-848-3700Fax: 248-848-3701www.concrete.orgACI ITG-4.3R-07 was published and became effective August 2007.Copyright 2007, American Concrete Institute.All rights reserved including rights of reproduction and use in any form or by anymeans, including the making of copi
12、es 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-4.3R-1ACI Committee Reports, Gu
13、ides, Standard Practices, andCommentaries are intended for guidance in planning,designing, executing, and inspecting construction. Thisdocument is intended for the use of individuals who arecompetent to evaluate the significance and limitations of itscontent and recommendations and who will acceptre
14、sponsibility 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 made in contractdocuments. If
15、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.Report on Structural Design and Detailing forHigh-Strength Concrete in Moderate toHigh Seismic Applications
16、Reported by ACI Innovation Task Group 4 and Other ContributorsACI ITG-4.3R-07ACI ITG-4.3R presents a literature review on seismic design using high-strength concrete. The document is organized in chapters addressing thestructural design of columns, beams, beam-column joints, and structuralwalls made
17、 with high-strength concrete, and focuses on aspects most relevantfor seismic design. Each chapter concludes with a series of recommendedmodifications to ACI 318-05 based on the findings of the literature review.The recommendations include proposals for the modification of the equiva-lent rectangula
18、r stress block, equations to calculate the axial strength ofcolumns subjected to concentric loading, column confinement requirements,limits on the specified yield strength of confinement reinforcement, strutfactors, and provisions for the development of straight bars and hooks.An accompanying standa
19、rd, ITG-4.1, is written in mandatory languagein a format that can be adopted by local jurisdictions, and will allow buildingofficials to approve the use of high-strength concrete on projects that arebeing constructed under the provisions of ACI 301, “Specifications forStructural Concrete,” and ACI 3
20、18, “Building Code Requirements forStructural Concrete.”ITG 4 has also developed another nonmandatory language document:ITG-4.2R. It addresses materials and quality considerations and isthe supporting document for ITG-4.1.Keywords: bond; confinement; drift; flexure; high-strength concrete; high-yiel
21、d-strength reinforcement; seismic application; shear; stress block; strut-and-tie.CONTENTSChapter 1Introduction, p. ITG-4.3R-21.1Background1.2ScopeChapter 2Notation, p. ITG-4.3R-4Chapter 3Definitions, p. ITG-4.3R-7Chapter 4Design for flexural and axial loads using equivalent rectangular stress block
22、,p. ITG-4.3R-74.1Parameters of equivalent rectangular stress block4.2Stress intensity factor 14.3Stress block depth parameter 14.4Stress block area 14.5Limiting strain cu4.6Axial strength of high-strength concrete columns4.7Comparison of different proposals for rectangularstress block4.8Recommendati
23、onsChapter 5Confinement requirements for beams and columns, p. ITG-4.3R-195.1Constitutive models for confined concrete5.2Previous research and general observations5.3Equations to determine amount of confinementreinforcement required in columnsJoseph M. Bracci D. Kirk Harman Adolfo MatamorosMichael A
24、. Caldarone Daniel C. Jansen Andrew W. TaylorOther contributorsDominic J. Kelly Andres Lepage Henry G. RussellACI Innovation Task Group 4S. K. GhoshChairITG-4.3R-2 ACI COMMITTEE REPORT5.4Definition of limiting drift ratio on basis of expecteddrift demand5.5Use of high-yield-strength reinforcement fo
25、rconfinement5.6Maximum hoop spacing requirements for columns5.7Confinement requirements for high-strength concretebeams5.8Maximum hoop spacing requirements for high-strength concrete beams5.9RecommendationsChapter 6Shear strength of reinforced concrete flexural members, p. ITG-4.3R-356.1Shear streng
26、th of flexural members without shearreinforcement6.2Effect of compressive strength on inclined crackingload of flexural members6.3Effect of compressive strength on flexural memberswith intermediate to high amounts of transversereinforcement6.4Shear strength of members with low shear span-depth ratio
27、s6.5Calculation of shear strength of members subjectedto seismic loading6.6Use of high-strength transverse reinforcement6.7RecommendationsChapter 7Development length/splices,p. ITG-4.3R-447.1Design equations for development length of bars inhigh-strength concrete7.2Design equations for development l
28、ength of hookedbars in high-strength concrete7.3RecommendationsChapter 8Design of beam-column joints,p. ITG-4.3R-488.1Confinement requirements for beam-column joints8.2Shear strength of exterior joints8.3Shear strength of interior joints8.4Effect of transverse reinforcement on joint shearstrength8.5
29、Development length requirements for beam-columnjoints8.6RecommendationsChapter 9Design of structural walls, p. ITG-4.3R-519.1Boundary element requirements9.2Shear strength of walls with low aspect ratios9.3Minimum tensile reinforcement requirements in walls9.4RecommendationsChapter 10List of propose
30、d modifications toACI 318-05, p. ITG-4.3R-5310.1Proposed modifications to equivalent rectangularstress block10.2Proposed modifications related to confinement ofpotential plastic hinge regions10.3Proposed modifications related to bond and develop-ment of reinforcement10.4Proposed modifications relate
31、d to strut-and-tiemodelsAcknowledgments, p. ITG-4.3R-56Chapter 11Cited references, p. ITG-4.3R-56CHAPTER 1INTRODUCTION1.1BackgroundThe origin of ACI Innovation Task Group (ITG) 4, High-Strength Concrete for Seismic Applications, can be tracedback to the International Conference of Building Officials
32、(ICBO) (now International Code Council ICC) EvaluationReport ER-5536, “Seismic Design Utilizing High-StrengthConcrete” (ICBO 2001). Evaluation Reports (ER) are issuedby Evaluation Service subsidiaries of model code groups. AnER essentially states that although a particular method,process, or product
33、 is not specifically addressed by a particularedition of a certain model code, it is in compliance with therequirements of that particular edition of that model code.ER-5536 (ICBO 2001), first issued in April 2001, wasgenerated by Englekirk Systems Development Inc. for theseismic design of moment-re
34、sisting frame elements usinghigh-strength concrete. High-strength concrete was definedas “normalweight concrete with a design compressivestrength greater than 6000 psi (41 MPa) and up to amaximum of 12,000 psi (83 MPa).” It was based on researchcarried out at the University of Southern California an
35、d theUniversity of California at San Diego to support buildingconstruction in Southern California using concrete withcompressive strengths greater than 6000 psi (41 MPa).The Portland Cement Association performed a review*ofER-5536 and brought up several concerns that focused oninconsistencies betwee
36、n the evaluation report and existingindustry documents in two primary areas: material andstructural. Despite those concerns, it was evident that theevaluation report had been created because quality assuranceand design provisions were needed by local jurisdictions, suchas the City of Los Angeles, to
37、 allow the use of high-strengthconcrete without undue restrictions. ACI has assumed aproactive role in the development of such provisions with thegoal of creating a document that can be adopted nationwide.ACI considered its own Committee 363, High StrengthConcrete, to be the best choice to address t
38、he materials andquality aspects of the document, while ACI Subcommittee318-H, Structural Concrete Building CodeSeismicProvisions, was considered the best choice to address theseismic detailing aspects. Because 318-H is a subcommitteeof a code-writing body, the development of a technicaldocument of t
39、his kind is not part of its intended mission. Inaddition, producing a document through a technicalcommittee can be a lengthy process. Based on these limitations,a request was made to form an ITG that would have theadvantage of following a shorter timeline to completion. In*Unpublished report availab
40、le from PCA, Skokie, Ill., Aug. 2001.STRUCTURAL DESIGN AND DETAILING FOR HIGH-STRENGTH CONCRETE IN SEISMIC APPLICATIONS ITG-4.3R-3response to the request, the Technical Activities Committee(TAC) of ACI approved the formation of ITG 4 and estab-lished its mission. The mission was to develop an ACIdoc
41、ument that addressed the application of high-strengthconcrete in structures located in areas of moderate and highseismicity. The document was intended to cover structuraldesign, material properties, construction procedures, andquality-control measures. It was to contain language in a formatthat allo
42、wed building officials to approve the use of high-strength concrete in projects being constructed under theprovisions of ACI 301-05, “Specifications for StructuralConcrete,” and ACI 318, “Building Code Requirements forStructural Concrete.”The concept of “moderate to high seismic applications,”stated
43、 in the mission of the document, dates back to whenU.S. seismic codes divided the country into seismic zones.These seismic zones were defined as regions in whichseismic ground motion on rock, corresponding to a certainprobability of occurrence, remained within certain ranges.Present-day seismic code
44、s (ASCE/SEI 2006) follow adifferent approach to characterizing a seismic hazard. Giventhat public safety is a primary code objective, and that not allbuildings in a given seismic zone are equally crucial topublic safety, a new mechanism for triggering seismicdesign requirements and restrictions, cal
45、led the seismicperformance category (SPC), was developed. The SPCclassification includes not only the seismicity at the site, butalso the occupancy of the structure.Recognizing that building performance during a seismicevent depends not only on the severity of bedrock acceleration,but also on the ty
46、pe of soil that a structure is founded on,seismic design criteria in more recent seismic codes arebased on seismic design categories (SDC). The SDC is afunction of location, building occupancy, and soil type.The TAC Technology Transfer Committee (TTTC)-estab-lished mission of ITG 4 was interpreted t
47、o mean that theTask Group was to address the application of high-strengthconcrete in structures that are:Located in Seismic Zones 2, 3, or 4 of the “UniformBuilding Code” (ICBO 1997); orAssigned to SDC C, D, or E of “The BOCA NationalBuilding Code” (BOCA 1993 and subsequent editions)or the “Standard
48、 Building Code” (SBCCI 1994); orSDC C, D, E, or F of the “International Building Code”(IBC 2003) or the National Fire Protection Association(NFPA) NFPA 5000 “Building Construction and SafetyCode” (2003).SPC or SDC C is also referred to as the “intermediate”category. Similarly, SPC D and E or SDC D,
49、E, and F arereferred to as “high” categories. The terminology “moderateto high seismic applications,” however, is used throughoutthis document.1.2ScopeThis document addresses the material and design consider-ations when using normalweight concretes having specifiedcompressive strengths of 6000 psi (41 MPa) or greater instructures designed for moderate to high seismic applications.Irrespective of seismic zone, SPC, or SDC, this document isalso applicable to normalweight high-strength concrete inintermediate or special moment fra
