ACI 355.3R-2011 Guide for Design of Anchorage to Concrete Examples Using ACI 318 Appendix D.pdf

1、Reported by ACI Committee 355ACI 355.3R-11Guide for Design of Anchorageto Concrete: Examples UsingACI 318 Appendix DGuide for Design of Anchorage to Concrete:Examples Using ACI 318 Appendix DFirst printingMay 2011ISBN 978-0-87031-425-4American Concrete InstituteAdvancing concrete knowledgeCopyright

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11、55.3R-11 was adopted and published March 2011.Copyright 2011, 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, written, or oral, or

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14、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 made in contractdocuments. If items found in this document are desired by theArchitect/Engineer to be a part of the contract documents, they

15、shall be restated in mandatory language for incorporation bythe Architect/Engineer.Guide for Design of Anchorage to Concrete:Examples Using ACI 318 Appendix DReported by ACI Committee 355ACI 355.3R-11This guide presents worked examples using the design provisions in ACI318 Appendix D. Not all condit

16、ions are covered in these examples. Theessentials of direct tension, direct shear, combined tension and shear, andthe common situation of eccentric shear, as in a bracket or corbel, arepresented.Keywords: anchorage; combined tension and shear; design examples;eccentric shear; embedded bolts; headed-

17、stud anchors; post-installedanchors; shear; tension.CONTENTSChapter 1Introduction, p. 21.1Introduction1.2Discussion on design example problems1.3Commentary on seismic requirements for Appendix Dof ACI 318-02 and ACI 318-051.4Commentary on seismic requirements for Appendix Dof ACI 318-081.5Commentary

18、 on notation and definitions forAppendix D ACI 318-081.6Anchor designs featured in example problemsChapter 2Notation and definitions, p. 42.1Notation2.2DefinitionsChapter 3ACI 318-05 Appendix D (reprinted),p. 7Chapter 4Design examples, p. 354.1Example 1: Single headed anchor away from edgessubjected

19、 to seismic tension4.2Example 2: Single hooked anchor away from edgessubjected to seismic tension4.3Example 3: Single post-installed anchor in tensionaway from edges4.4Example 4: Group of headed studs in tension nearan edge4.5Example 5: Single headed bolt in shear near an edge4.6Example 6: Single he

20、aded bolt in tension and shearnear an edge4.7Example 7: Single post-installed anchor in tensionand shear near an edgeTarek S. Aziz Werner A. F. Fuchs Richard E. Klingner*Jake OlsenRanjit L. Bandyopadhyay*Branko Galunic Anthony J. Lamanna Alan D. PricePeter J. Carrato*Brian C. Gerber Harry B. Lancelo

21、t III John F. Silva*Harry A. Chambers Michael Gong Nam-Ho Lee*Patrick J. E. SullivanRonald A. Cook*Herman L. Graves III Lee W. Mattis Harry WiewelRolf Eligehausen Christopher Heinz*Robert R. McGlohn*Richard E. WollmershauserSam S. Eskildsen*Bruce I. Ireland*Committee 355 members who were major contr

22、ibutors to the development of this guide.Deceased.Donald F. Meinheit*ChairJ. Bret Turley*Secretary2 GUIDE FOR DESIGN OF ANCHORAGE TO CONCRETE: EXAMPLES USING ACI 318 APPENDIX D (ACI 355.3R-11)American Concrete Institute Copyrighted Materialwww.concrete.org4.8Example 8: Group of cast-in anchors in te

23、nsion and shearwith two free edges and supplemental reinforcement4.9Example 9: Group of headed studs in tension near anedge with eccentricity4.10Example 10: Multiple headed anchor connectionsubjected to moment and shear4.11Example 11: Multiple post-installed anchorconnection subjected to seismic mom

24、ent and shear4.12Example 12: Multiple headed anchor connectionsubjected to seismic moment and shear4.13Example 13: Group of tension anchors on a pierwith shear lugChapter 5References, p. 1185.1Referenced standards and reports5.2Cited referencesAppendix ATables, p. 119Table A.1Materials for headed an

25、chors and threaded rodsTable A.2(a)Bearing area (Abrg) for cast-in anchors,threaded rod with nuts, and threaded rodswith nuts and washersTable A.2(b)Dimensional properties of bolts and studsfor determining bearing area (Abrg)Table A.2(c)Dimensional properties of nuts fordetermining bearing area (Abr

26、g)Table A.3Sample data for a post-installed, torque-controlled mechanical expansion anchorTable A.4Sample data for a post-installed, undercut anchorCHAPTER 1INTRODUCTION1.1IntroductionThis guide was prepared by the members of ACI 355,Anchorage to Concrete, to provide design examples thatdemonstrate

27、the provisions of ACI 318-05 Appendix D.Appendix D, which was first introduced in ACI 318-02,contains design provisions for determining the strength ofanchors based on the Concrete Capacity Design (CCD)method for concrete breakout failure. The CCD method hasits origins in research work done at the U

28、niversity of Stuttgartin Germany (Eligehausen et al. 1987; Eligehausen and Fuchs1988; Rehm et al. 1992) and was formalized at the Univer-sity of Texas at Austin in the 1990s (Fuchs et al. 1995). TheCCD method calculates the concrete breakout strength usinga model that is based on a breakout prism ha

29、ving an angle ofapproximately 35 degrees, rather than the traditional 45-degree cone model used since the early 1970s.Appendix D design provisions are for both cast-in-placeanchors and prequalified post-installed mechanical anchors.Separate design equations are frequently provided becausecast-in-pla

30、ce anchors behave differently than post-installedanchors. The provisions for post-installed anchors are onlyintended for those post-installed anchors that are qualifiedunder comprehensive testing protocols. The testing and evalua-tion requirements in ACI 355.2 are the standard for qualifyingpost-ins

31、talled anchors used in design with Appendix D.Similar procedures, which are expected to be completedsoon, are under development for adhesive anchors andconcrete screw anchors.1.2Discussion on design example problemsThe example problems presented in this guide were developedusing the code provisions

32、in Appendix D of ACI 318-05,which were current at the time the examples were developed.The new provisions of ACI 318-08 will alter the calculationsand results in these examples. Commentary in this guidedescribes how the new ACI 318-08 provisions modify thedesign results. The ACI 318-08 Appendix D pr

33、ovisionsclarify issues when dealing with earthquake forces, ductilefailure, anchor reinforcement, and supplemental reinforcement.The design approach used in the example problems followsa basic outline of evaluating each potential failure mode intension and shear for the anchor using the provisions o

34、fAppendix D of ACI 318-05. The provisions include modifica-tion factors that account for the effects of edges, eccentricity,and the presence or lack of cracking in the concrete, todetermine the nominal strengths for each failure mode. Thetypes of failure modes considered are shown in Table 1.1.In ad

35、dition to the failure modes in Table 1.1, minimumedge distance, anchor spacing, and thickness of the concretemember are checked to preclude the splitting of concrete.The calculated nominal strengths for each failure mode aremodified by the appropriate modification factors. Theminimum calculated desi

36、gn strength becomes the controllingdesign strength of the anchor or group of anchors.1.3Commentary on seismic requirements for Appendix D of ACI 318-02 and ACI 318-05ACI 318-02 and ACI 318-05 use the terminology “low,”“moderate,” and “high” to describe the levels of seismic risk.The design strength

37、of anchors that include earthquakeforces and that are located in regions of moderate or highseismic risk are required to be controlled by failure in tension,shear, or both, of a ductile steel element. In addition, thedesign strengths for steel and concrete are reduced by a factorof 0.75. The nonduct

38、ile, concrete failure modes include all theconcrete breakout modes in tension and shear, plus the pulloutand pull-through failure modes in tension. Nonductile failurecan occur if the steel behaves in a brittle fashion. It is notalways possible, due to geometric or material constraints, todesign the

39、anchorage for a ductile failure. Therefore, codeprovisions allow the attachment, which the anchor connects tothe structure, to be considered as the ductile steel element.Design Examples 1, 2, 11, and 12 demonstrate the provisionsof Appendix D when earthquake forces are involved. Theyshow the design

40、of the anchors governed by the steel strengthof a ductile steel element, according to Section D.3.3.4 ofTable 1.1List of anchor failure modesTension failure mode Shear failure modeSteel strength of anchor Steel strength of anchor Concrete breakout strength Concrete breakout strength Concrete side-fa

41、ce blowout strength Concrete pryout strength Pullout and pull-through strengthGUIDE FOR DESIGN OF ANCHORAGE TO CONCRETE: EXAMPLES USING ACI 318 APPENDIX D (ACI 355.3R-11) 3American Concrete Institute Copyrighted Materialwww.concrete.orgACI 318-05, thus avoiding the potential problem of brittlefailur

42、e associated with concrete breakout.1.4Commentary on seismic requirements for Appendix D of ACI 318-08Several changes were made from the previous seismicrequirements for Appendix D stated in Section 1.3 of thisguide. The levels of seismic risk from previous ACI 318editions have been correlated in AC

43、I 318-08 to the corre-sponding design methods, categories, and zones shown in themodel building codes. The seismic reduction factor of 0.75that is applied to the design strength of ductile steel has beeneliminated. For Examples 1, 2, 11, and 12, which are discussedin Section 1.3 of this guide, the r

44、emoval of this reduction factorfor steel would indicate that a brittle concrete breakout failurewould control the design in most cases. Nonductile failuremodes are allowed to control seismic design in ACI 318-08 byimposing an additional reduction factor of 0.4 to the concretebreakout strength. This

45、factor, when combined with therequired seismic reduction factor of 0.75, which is associatedwith concrete failure modes, results in a total reduction of 0.3,and reduces the concrete breakout design strength from the ACI318-05 levels. The intent of reducing the permissible strength isto force the anc

46、horage system to resist the earthquake loadelastically and avoid brittle failure in the concrete.1.5Commentary on notation and definitions for Appendix D ACI 318-08A new definition, “anchor reinforcement” has beendefined in ACI 318-08 Appendix D to include the situationwhere reinforcing steel is spe

47、cifically designed to transferall the anchorage forces into the structure without consideringthe concrete breakout strength. This anchor reinforcementdesign approach occurs in cases where the concretebreakout strength is insufficient due to geometricrestraints. Example 13 provides information on des

48、igningthe anchorage using anchor reinforcement. Adding thisnew definition helped to distinguish the term from supple-mental reinforcement. Supplemental reinforcementpresent in the direction of the load can provide restraintand improve ductility for the anchorage. Although supple-mental reinforcement

49、 is not explicitly designed to transferthe load, it has been experimentally shown to improveductility, thereby allowing an increase in the designstrength of the connection through an increase in the phifactor. Examples 8 and 10 demonstrate the use of supple-mental reinforcement.A new term c,Vhas been included in ACI 318-08Appendix D to provide a modification factor to increase thebasic concrete breakout strength in shear when the thicknessof the section, ha, is less than 1.5ca1.The term for anchor diameter was changed from doto dain ACI 318-08