1、ACI 307-08Reported by ACI Committee 307Code Requirements for ReinforcedConcrete Chimneys (ACI 307-08)and CommentaryAn ACI StandardCode Requirements for Reinforced Concrete Chimneysand CommentaryFirst PrintingNovember 2008ISBN 978-0-87031-307-3American Concrete InstituteAdvancing concrete knowledgeCo
2、pyright 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 technical committees res
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4、ct. 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/committees/errata.asp for the most up-to-date revisions.ACI committee documents are intended for the use of indivi
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10、 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 Club DriveFarmington Hills, MI 48331U.S.A.Phone: 248-848-3700Fax: 248-848-3701www.concrete.orgACI 307-08 supersedes
11、ACI 307-98, was adopted August 19, 2008, and publishedNovember 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, printed,
12、 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.307-1ACI Committee Reports, Guides, Manuals, StandardPractices, and Commentaries are intended for guidance
13、 inplanning, designing, executing, and inspecting construction.This Commentary is intended for the use of individuals whoare competent to evaluate the significance and limitations of itscontent and recommendations and who will acceptresponsibility for the application of the material it contains.The
14、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 Commentary shall not be made in contractdocuments. If items found in this document are desired by thelicensed design
15、professional to be a part of the contractdocuments, they shall be restated in mandatory language.ACI 307-08This code gives material, construction, and design requirements for cast-in-place and precast reinforced concrete chimneys. It sets forth minimumloadings for design and contains methods for det
16、ermining the concrete andreinforcement required as a result of these loadings. The method of analysisapplies primarily to circular chimney shells; however, a general procedurefor analysis of noncircular shapes is included.Equations are provided for determining the temperature gradient throughthe con
17、crete resulting from the difference in temperature of the gases insidethe chimney and the surrounding atmosphere. Methods for combining theeffects of dead and wind (or earthquake) loads with temperature, bothvertically and circumferentially, are included in this code. These methodspermit the license
18、d design professional to establish minimum concrete andreinforcement requirements.The Commentary discusses some of the background and considerationsof Committee 307 in developing the provisions contained in “CodeRequirements for Reinforced Concrete Chimneys (ACI 307-08).” Twoappendixes provide the d
19、erivation of the equations for nominal strengthand temperature stresses. Commentary provisions begin with an “R,” suchas “R1.1.1,” and are shown in italics.Keywords: chimneys; compressive strength; concrete construction; earth-quake-resistant structures; formwork (construction); foundations; hightem
20、perature; linings; loads (forces); moments; openings; precast concrete;quality control; reinforced concrete; reinforcing steels; specifications;static loads; strength; structural analysis; structural design; temperature;thermal gradient; wind pressure.CONTENTSR0Introduction, p. 307-2Chapter 1General
21、, p. 307-31.1Scope1.2Drawings1.3Regulations1.4NotationChapter 2Materials, p. 307-72.1General2.2Cement2.3Aggregates2.4ReinforcementChapter 3Construction requirements, p. 307-73.1General3.2Concrete strength3.3Strength tests3.4Forms3.5Reinforcement placement3.6Concrete placement3.7Concrete curing3.8Con
22、struction tolerances3.9Precast erectionChapter 4Loads and general design criteria,p. 307-84.1General4.2Wind loadsVictor A. Bochicchio Thomas D. Joseph Robert A. Porthouse Randolph W. SnookJohn J. Carty Jagadish R. Joshi Ronald E. Purkey John C. SowizalSamuel Dilcer Faris A. Malhas Denis J. Radecki B
23、arry J. VickeryShu-Jin Fang David C. Mattes Scott D. Richart Edward L. YordySigmund A. FreemanThe committee acknowledges the late Milton Harstein for his contribution to the development of these code requirements.David J. BirdChairCode Requirements for Reinforced Concrete Chimneys (ACI 307-08) and C
24、ommentaryAn ACI StandardReported by ACI Committee 307307-2 ACI STANDARD4.3Earthquake loads4.4Special design considerations and requirements4.5Wind deflection criteriaChapter 5Design of chimney shells: strength method, p. 307-175.1General5.2Design loads5.3Required strength5.4Design strength5.5Nominal
25、 moment strength: circular shells5.6Noncircular shapes5.7Design for circumferential bendingChapter 6Thermal stresses, p. 307-226.1General6.2Vertical temperature stresses6.3Circumferential temperature stressesChapter 7References, p. 307-237.1/R7.1Referenced standards/Referenced standardsand reportsR7
26、.2Cited referencesAppendix ADerivation of equations for nominal strength, p. 307-25Appendix BDerivation of equations for temperature stresses, p. 307-29R0INTRODUCTIONAs industry expanded in the years immediately followingWorld War I and, as a result of the development of largepulverized coal-fired b
27、oilers for the electric power-generatingutilities in the 1920s, a number of large reinforced concretechimneys were constructed to accommodate these newfacilities. A group of interested engineers who foresaw thepotential need for many more such chimneys, and who weremembers of the American Concrete I
28、nstitute, embarked onan effort to develop rational design criteria for these structures.The group was organized into ACI Committee 505 (predecessorto the present Committee 307) to develop such criteria in theearly 1930s.Committee 505 submitted a “Proposed Standard Specifica-tion for the Design and C
29、onstruction of Reinforced ConcreteChimneys,” an outline of which was published in the ACIJOURNAL (ACI Committee 505 1934). This specification wasadopted as a tentative standard in February 1936. Althoughthis tentative standard was never accepted by ACI as anofficial standard, it was used as the basi
30、s for the design ofmany chimneys. As these chimneys aged, inspectionsrevealed considerable cracking. When the industrial expansionbegan following World War II, other engineers recognizedthe need for developing an improved design specification forreinforced concrete chimneys.In May 1949, Committee 50
31、5 was reactivated to revise thetentative standard specification, embodying modifications thatwere found desirable during the years it had been in use. Thesection dealing with the temperature gradient through thechimney lining and the chimney shell was completely revisedand extended to cover differen
32、t types and thicknesses of liningsand both unventilated and ventilated air spaces between thelining and the concrete shell. In 1954, this specification wasapproved as ACI 505-54 (ACI Committee 505 1954).The rapid increase in the size and height of concrete chimneysbeing built in the mid-1950s raised
33、 further questions about theadequacy of the 1954 version of the specification, especially inrelation to earthquake forces and the effects of wind.In May 1959, the ACI Board of Direction reactivatedCommittee 505 (renamed Committee 307) to review thestandard and to update portions with the latest desi
34、gntechniques and the then-current knowledge of the severity ofthe operating conditions that prevailed in large steamplants. The material in the standard was reorganized, chartswere added, and the methods for determining loads due towind and earthquakes were revised. The information ondesign and cons
35、truction of various types of linings wasamplified and incorporated in an appendix. That versionincluded criteria for working stress design. It was planned toadd ultimate strength criteria in a future revision.In preparing the earthquake design recommendations forACI 307-69 (ACI Committee 307 1969),
36、the committeeincorporated the results of theoretical studies by adaptingthem to existing United States codes. The primary problemsin this endeavor stemmed from the uncertainties stillinherent in the definition of earthquake forces and from thedifficulty of selecting the proper safety and serviceabil
37、itylevels that might be desirable for various classes ofconstruction. Committee investigations revealed that withsome modifications (such as the K factor), the base shearequations developed by the Seismology Committee of theStructural Engineers Association of California (SEAOC)could be applied to ch
38、imneys. Similarly, the shape of theforce, shear, and moment distributions, as revised in their1967 report, were also suitable for chimneys. A use factor(U factor) ranging from 1.3 to 2.0 was introduced in thespecification, and it was emphasized that the requirements ofSection 4.5 of ACI 307-69 that
39、related to seismic designcould be superseded by a rational analysis based on evaluationof the seismicity of the site and modal response calculations.The modifications were approved in ACI 307-69. In thatversion, the commentary and derivation of equations werepublished separately as a supplement to A
40、CI 307-69.In 1970, the document was reissued with corrections oftypographical errors. This issue of ACI 307-69 was alsodesignated ANSI A158.1-1970. At the time, as a result ofnumerous requests, the commentary and derivation ofequations were bound together with the specification.ACI 307-79 (ACI Commi
41、ttee 307 1979) updated itsrequirements to agree with the then-accepted standardpractices in the design and construction of reinforced concretechimneys. The major changes included the requirement thattwo layers of reinforcing steel be used in the walls of allchimneys (previously, this only applied to
42、 chimney wallsthicker than 18 in.) and the requirement that horizontalsections through the chimney wall be designed for the radialwind pressure distribution around the chimney. FormulasREINFORCED CONCRETE CHIMNEYS 307-3were included to compute the stresses under these conditions.Many revisions of le
43、ss importance were included to bring thespecification up to date.The editions of the specifications before 1979 includedappendixes on the subjects of chimney linings and accessories.In 1971, Committee 307 learned of buckling problems insteel chimney liners. The committee also noted that, in modernpo
44、wer plant and process chimneys, environmental regulationsrequired treatment of the effluent gases that could result inextremely variable and aggressively corrosive conditions inthe chimneys. These facts led the committee to agree that thetask of keeping the chimney liner recommendations current wasn
45、ot a responsibility of an ACI committee and could bemisleading to licensed design professionals using thechimney specification. By committee consensus, the referenceto chimney liner construction was dropped from futureeditions of the specification. Committee 307 then made arecommendation to the Bric
46、k Manufacturers Associationand the American Society of Civil Engineers that eachappoint a task force or a committee for the development ofdesign criteria for brick and steel liners, respectively. ThePower Division of ASCE took up the recommendation andappointed a task committee that developed and pu
47、blished adesign guide in 1975 titled “Design and Construction of SteelChimney Liners” (ASCE Task Committee on Steel ChimneyLiners 1975). ASTM established two task forces for chimneyliners: one for brick and one for fiberglass-reinforced plastic.The committee had extensive discussion on the question
48、ofincluding strength design in the 1979 specification. Thedecision to exclude it was based on the lack of experimentaldata on hollow concrete cylinders to substantiate this formof analysis for concrete chimneys. The committee continued,however, to consider strength design, and encouragedexperiments
49、in this area.Shortly after ACI 307-79 was issued, the committeedecided to incorporate strength design provisions andupdate the wind and earthquake design requirements.ACI 307-88 (ACI Committee 307 1988) incorporatedsignificant changes in the procedures for calculating windforces as well as requiring strength design rather thanworking stress. The effects of these and other revisionsresulted in designs with relatively thin walls governed mainlyby steel area and, in many instances, across-wind forces.The subject of across-wind loads dominated the
