ACI 550.2R-2013 Design Guide for Connections in Precast Jointed Systems.pdf

1、ACI 550.2R-13Design Guide for Connections in Precast Jointed SystemsReported by Joint ACI-ASCE Committee 550First PrintingApril 2013Design Guide for Connections in Precast Jointed Systems Copyright by the American Concrete Institute, Farmington Hills, MI. All rights reserved. This material may not b

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10、hat it develops.Order information: ACI documents are available in print, by download, on CD-ROM, through electronic subscription, or reprint and may be obtained by contacting ACI.Most ACI standards and committee reports are gathered together in the annually revised ACI Manual of Concrete Practice (M

11、CP).American Concrete Institute38800 Country Club DriveFarmington Hills, MI 48331U.S.A.Phone: 248-848-3700Fax: 248-848-3701www.concrete.orgISBN-13: 978-0-87031-812-2ISBN: 0-87031-812-8American Concrete InstituteAdvancing concrete knowledgeThe proper detailing and design of precast concrete connectio

12、ns are essential to the performance of a precast concrete structure. This guide provides information on design, detailing, and construc-tion of connections between precast members in jointed systems, including moment frame and structural wall systems.Keywords: bolting; connection; debonding; ductili

13、ty; erection; moment frame; precast; pretopped; post-tensioning; structural walls; welding.CONTENTSCHAPTER 1INTRODUCTION AND SCOPE, p. 21.1Introduction, p. 21.2Scope, p. 2CHAPTER 2NOTATION AND DEFINITIONS, p. 22.1Notation, p. 22.2Definitions, p. 2CHAPTER 3GUIDELINES FOR DESIGN, p. 33.1Classes of con

14、nections, p. 33.2Principles of connection design, p. 33.3Anchorage to concrete, p. 53.4Welding, p. 53.5Debonding, p. 7CHAPTER 4PRECAST CONCRETE FLOOR SYSTEMS, p. 74.1Precast systems, p. 74.2Precast floor diaphragms, p. 7CHAPTER 5LATERAL-LOAD-RESISTING SYSTEMS, p. 85.1Structural walls, p. 85.2Structu

15、ral walls with large openings, p. 85.3Moment frames, p. 8CHAPTER 6CONNECTIONS, p. 106.1Strength, p. 106.2Ductility, p. 106.3Volume change accommodation, p. 116.4Durability, p. 116.5Fire resistance, p. 116.6Constructibility, p. 116.7Aesthetics, p. 116.8Seismic requirements, p. 116.9Tolerances, p. 116

16、.10Vertical connections, p. 11CHAPTER 7ERECTION CONSIDERATIONS, p. 13CHAPTER 8WELDING CONSIDERATIONS, p. 138.1Steel assemblies, p. 13ACI 550.2R-13Design Guide for Connections in Precast Jointed SystemsReported by Joint ACI-ASCE Committee 550Te-Lin ChungNed M. ClelandWilliam K. DoughtyAlvin C. Ericso

17、nMelvyn A. GalinatHarry A. GleichMohammad S. HabibNeil M. HawkinsAugusto H. HolmbergL. S. Paul JohalJason J. KrohnEmily B. LorenzKenneth A. LuttrellVilas S. MujumdarFrank A. NadeauClifford R. OhlwilerVictor F. Pizano-ThomenJose I. RestrepoSami H. RizkallaMario E. RodriguezJoseph C. SandersJohn F. St

18、antonP. Jeffrey WangCloyd E. WarnesThomas J. DArcy, Chair1ACI Committee Reports, Guides, and Commentaries are intended for guidance in planning, designing, executing, and inspecting construction. This document is intended for the use of individuals who are competent to evaluate the significance and

19、limitations of its content and recommendations and who will accept responsibility for the application of the material it contains. The American Concrete Institute disclaims any and all responsibility for the stated principles. The Institute shall not be liable for any loss or damage arising therefro

20、m.Reference to this document shall not be made in contract documents. If items found in this document are desired by the Architect/Engineer to be a part of the contract documents, they shall be restated in mandatory language for incorporation by the Architect/Engineer.ACI 550.2R-13 was adopted and p

21、ublished April 2013.Copyright 2013, American Concrete Institute.All rights reserved including rights of reproduction and use in any form or by any means, including the making of copies by any photo process, or by electronic or mechanical device, printed, written, or oral, or recording for sound or v

22、isual reproduc-tion or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors.8.2Galvanized steel, p. 138.3Stainless steel, p. 148.4Reinforcement, p. 148.5Welding practices for epoxy-coated material, p. 15CHAPTER 9GROUTING, p.

23、15CHAPTER 10REFERENCES, p. 15CHAPTER 1INTRODUCTION AND SCOPE1.1IntroductionPrecast concrete structural systems are composed of indi-vidually fabricated components. Because of the segmental nature of precast concrete construction, connections between individual components are required to support the

24、design loads. Connections are also required to accommodate defor-mations, including rotations and strains.1.1.1 Connection methodsPrecast components are connected by one of two methods. The first method connects components by reinforcement that protrudes from each component end, spliced using propri

25、etary hardware or by lap-splicing with a small quantity of cast-in-place concrete to complete the connection. This method is referred to as emulation, or a wet connection, because it involves field-placed cast-in-place concrete and mimics the behavior of cast-in-placed monolithic structures. The sec

26、ond, more-common, method of connection is dry and connects compo-nents by welding, bolting, post-tensioning, or doweling without using field-placed concrete. Because dry connec-tions are typically less stiff than their connecting precast components, deformations tend to be concentrated in the connec

27、tions.Connections should allow for easy and economical component casting and assembly, fabrication, erection clear-ance, and erection tolerances. They should also tolerate anticipated deformation without significant loss of strength.1.1.2 Connection groupsConnections are categorized into five groups

28、:1) Gravity load transferGravity loads alone, such ashollow core members placed on a beam ledge2) Shear transferEither vertical shear, horizontal shear,or both, such as a double-tee flange-to-flange connection3) Moment transferThe tension and compressionforces created by moment, such as a connection

29、 between a precast moment frame and its foundation4) Structural integrityCode-prescribed structuralintegrity forces; typically a connection with combination accommodations5) Combination connectionA combination of loads,such as moments and shearIn all cases, the load paths and external loads are acco

30、m-modated in all elements of connections (Fig. 1.1.2).Tying all precast members to each adjacent member is essential for structural integrity as required by Chapter 16 of ACI 318-11. Such connections, however, should not be so rigid as to prevent member rotation or volume change strains when require

31、d.1.2ScopeThis guide provides information on the characteristics and design of connections between precast concrete components and between precast components and cast-in-place construc-tion. The proper detailing and design of precast concrete connections are essential to the performance of a precast

32、 concrete structure.This guide describes typical precast jointed systems and their connection types, performance, and characteristics, and provides recommendations for design and construc-tion. Three classes of connections are identified and their characteristic and key design considerations given.

33、Also included are guidelines for designing connections and their anchorage, a description of precast systems, typical lateral-load-resisting systems, key design considerations, and erec-tion requirements including special welding considerations.CHAPTER 2NOTATION AND DEFINITIONS2.1NotationCd= deflect

34、ion amplification factorfc = specified compressive strength of concrete, psi (MPa)R = response modification factorf = strength reduction factor2.2DefinitionsACI provides a comprehensive list of definitions through an online resource, “ACI Concrete Terminology,” http:/terminology.concrete.org. Defini

35、tions provided herein complement that resource.deformable connectiona class of connection between precast members designed to either display significant flex-ibility or to yield, without losing strength, when subjected to expected deformations.Fig. 1.1.2Wall panel to foundation connection.American C

36、oncrete Institute Copyrighted Materialwww.concrete.org2 DESIGN GUIDE FOR CONNECTIONS IN PRECAST JOINTED SYSTEMS (ACI 550.2R-13)ductile connectiona class of connection between precast members designed to yield and show stable hyster-etic force-deformation response when subjected to expected reversed

37、cyclic deformations.jointthe location in a precast structural system where precast members intersect.gravity-only membera member of a framing system that supports mainly gravity loads and is not part of the lateral-load-resisting system.pretopped systema precast flooring system that employs a thicke

38、ned top flange on precast members (typi-cally double tees) provided in place of field-placed topping.strong connectiona class of connection between precast members in which the connection between precast members remains elastic while adjoining members experi-ence yielding when subjected to expected

39、deformations.CHAPTER 3GUIDELINES FOR DESIGN3.1Classes of connectionsSelection of the connection type between precast compo-nents is essential to precast concrete design. Connection types should be identified early in the design process based on their expected role in the structural system. Yielding

40、of reinforcement is common in reinforced concrete structures in response to severe forces such as earthquakes. Designers should consider the location of inelastic deformation in components and design them to accommodate the defor-mations without loss of service strength. The joint regions where prec

41、ast members come together are the most likely place for yielding in frames. In emulative concrete construc-tion, they are rendered ductile by the prescriptive detailing requirements of the International Building Code (IBC 2006). Three classes of connections are described: strong, ductile, and deform

42、able.3.1.1 StrongStrong connections use a hierarchical design approach to ensure yielding and strain hardening will take place away from the connection. Strong connections do not have to display ductile response. The absolute strength is less important than the ratio of capacity to demand. An exampl

43、e is a one-piece beam and column precast compo-nent connected at midspan of the beam. When the seismic moments at midspan are smaller than at support locations, yielding occurs in the precast beam at the column face. This approach is not employed as frequently as other solutions. The concept of crea

44、ting strong joints to force yielding in the precast members away from the joint, although feasible, is typically used where jointing occurs at frame inflection points (Fig. 3.1.1).3.1.2 DuctileDuctile connections, which possess signif-icant deformation capacity, are detailed in regions where inelast

45、ic deformations concentrate to form a part of the seismic-load-resisting system. Ductile connections display stable hysteresis loops when subjected to reversed cyclic loading. Their design follows a strength hierarchy to ensure yielding and cyclic strain hardening occurring at the connec-tion only.

46、Such connections can be welded; however, the strength of welds and embeds need to be stronger than the connecting plate. Ductile connections can also be made with splicing reinforcing bars by lapping or using proprietary splice sleeves. There should be sufficient strain capacity to sustain resistanc

47、e through the required movement.3.1.3 DeformableDeformable connections undergo deformations when the structure displaces. For example, a precast beam bearing on a rubber pad on a corbel allows rotation with little longitudinal resistance. Although rotation occurs, the vertical load-carrying strength

48、 is not impaired. The gravity-only members and connections in many seismic-resistant structuresprecast and otherwiseshould act this way. In the 1994 Northridge earthquake, a number of connections lost their integrity because they relied on gravity to remain in place (Iverson and Hawkins 1994). Under

49、 a horizontal load, unseating of deformable connectors should be prevented; therefore, where movement is expected, some measure of restraint is required. Note that in Fig. 3.1.3, the connections vertical support is maintained, but lateral movement is limited by the threaded rod in the sleeve.3.2Principles of connection designAn appropriate connection detail can be designed once its function has been defined. Use of the three classes of connections enables the designer to plan the behavior of the structure, rather than u