1、ACI 550.3-13Design Specification for Unbonded Post-Tensioned Precast Concrete Special Moment Frames Satisfying ACI 374.1 (ACI 550.3-13) and CommentaryAn ACI StandardReported by Joint ACI-ASCE Committee 550First PrintingNovember 2013Design Specification for Unbonded Post-Tensioned Precast Concrete Sp
2、ecial Moment Frames Satisfying ACI 374.1 and CommentaryCopyright by the American Concrete Institute, Farmington Hills, MI. All rights reserved. This material may not be reproduced or copied, in whole or part, in any printed, mechanical, electronic, film, or other distribution and storage media, with
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12、rete.orgISBN: 978-0-87031-850-4American Concrete InstituteAdvancing concrete knowledgeACI 550.3-13Design Specification for Unbonded Post-Tensioned Precast Concrete Special Moment Frames Satisfying ACI 374.1 (ACI 550.3-13) and CommentaryAn ACI StandardReported by Joint ACI-ASCE Committee 550Harry A.
13、Gleich, Chair Larbi M. Sennour, SecretaryTe-Lin ChungNed M. ClelandThomas J. DArcyWilliam K. DoughtyAlvin C. EricsonNeil M. HawkinsAugusto H. HolmbergL. S. Paul JohalJason J. KrohnEmily B. LorenzKenneth A. LuttrellVilas S. MujumdarFrank A. NadeauClifford R. OhlwilerLance OsborneVictor F. Pizano-Thom
14、enJose I. RestrepoSami H. RizkallaMario E. RodriguezJoseph C. SandersEdith G. SmithJohn F. StantonP. Jeffrey WangCloyd E. WarnesSubcommittee MembersSatyendra GhoshSuzanne Dow NakakiThis Standard defines requirements that may be used to design special hybrid moment frames composed of discretely joint
15、ed precast concrete beams post-tensioned to concrete columns. After a major earthquake, these hybrid moment frames should exhibit minimal damage in beam-column regions and negligible permanent displacements. Hybrid moment frames do not satisfy the prescriptive requirements of Chapter 21 of ACI 318-1
16、1 for frames of monolithic construction. According to 21.1.1.8 of ACI 318-11, their acceptance requires demonstration by experimental evidence and analysis that the frames have strength and toughness equal to or exceeding those provided by comparable monolithic reinforced concrete frames that satisf
17、y the prescriptive requirements of Chapter 21. This Standard describes the requirements that the licenseddesign professional may use to demonstrate, through analysis, that such frames have strength and toughness at least equal to those of comparable monolithic frames. This Standard is a revision of
18、the ACI T1.2 Standard.In this Standard, consistent with the format of ACI 318, the word “Section” is not included before a reference to a section of ACI 318. To more clearly designate a section of this Standard, however, the word “Section” is used before any reference to a section of this Standard.
19、Consistent with the format of ASCE/SEI 7, the word “Section” is also included before a reference to a section of ASCE/SEI 7.Keywords: drift ratio; earthquake-resistant design; energy dissipation; moment frame; post-tensioning; precast concrete; prestressed concrete; test module; toughness.CONTENTSCH
20、APTER 1GENERAL, p. 31.1Introduction, p. 31.2Scope, p. 41.3Structural drawings, p. 61.4Units, p. 6CHAPTER 2NOTATION AND DEFINITIONS, p. 72.1Notation, p. 72.2Definitions, p. 8CHAPTER 3REFERENCED STANDARDS, p. 10CHAPTER 4MATERIALS, p. 114.1General, p. 114.2Ducts, p. 114.3Energy-dissipating reinforcemen
21、t, p. 114.4Prestressing strands and tendons, p. 111ACI 550.3-13 supersedes T1.2-03, was adopted August 8, 2013, and was published November 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 o
22、f copies by any photo process, or by electronic or mechanical device, printed, written, or oral, or recording for sound or visual reproduc-tion or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors.R4MATERIALS, p. 114.5Inte
23、rface grout, p. 124.6Grout for anchorage of energy-dissipating reinforce-ment, p. 12CHAPTER 5FRAMING SYSTEM REQUIREMENTS, p. 135.1General, p. 135.2Strength, p. 135.3Drift, p. 135.4Moment frame characteristics, p. 145.5Distribution of moment frames within structures, p. 155.6Moment frame-floor slab i
24、nteractions, p. 16CHAPTER 6DESIGN REQUIREMENTS FOR BEAMS OF MOMENT FRAMES, p. 176.1Prestress, p. 176.2Beam design, p. 17CHAPTER 7REQUIREMENTS FOR BEAM-COLUMN INTERFACES OF MOMENT FRAMES, p. 197.1General, p. 197.2Prestress force, p. 197.3Interface grout, p. 197.4Energy-dissipating reinforcement, p. 2
25、07.5Nominal flexural strength, p. 207.6Probable flexural strength, p. 207.7Anchorage of energy-dissipating reinforcement, p. 237.8Distribution of flexural reinforcement, p. 25CHAPTER 8FRAME JOINTS, p. 268.1General, p. 26R9COMMENTARY REFERENCES, p. 27Authored references, p. 27American Concrete Instit
26、ute Copyrighted Materialwww.concrete.org2 SPECIFICATION FOR UNBONDED PT PRECAST CONCRETE SPECIAL MOMENT FRAMES SATISFYNG ACI 374.1CHAPTER 1GENERAL1.1IntroductionFor regions of high seismicity, 21.1.1.8 of ACI 318-11 permits the use of structural systems that do not meet the prescriptive requirements
27、 of Chapter 21 if certain experimental evidence and analysis are provided. The intent of ACI 374.1 is to define the minimum evidence required when attempting to validate the use of weak-beam, strong-column special moment frames in accordance with 21.1.1.8 of ACI 318-11.Before acceptance testing can
28、be undertaken, ACI 374.1 requires that a design procedure be developed for prototype moment frames having the generic form for which acceptance is sought, and that procedure be used to proportion the test modules. ACI 550.3-13 defines the requirements to be used for one specific type of moment frame
29、 that does not fully satisfy the prescriptive requirements of Chapter 21 of ACI 318-11. This moment frame has been validated for use in regions of high seismicity under ACI 374.1 and ACI 318. The moment frame uses precast concrete beams that are post-tensioned to precast or cast-in-place concrete co
30、lumns. The columns are continuous through the joints and the beams each span a single bay. This Standard describes the frame as hybrid because it combines post-tensioned and precast concrete construction and combines the use of deformed reinforcement that is designed to yield with unbonded post-tens
31、ioning tendons that are designed to remain essentially elastic during the design basis earthquake (DBE).In this specific type of hybrid frame, the post-tensioning tendons are unbonded. Horizontal reinforcing bars grouted in ducts located in the columns and in the top and bottom of the beams, and des
32、cribed in this Standard as energy-dissipating reinforcement, provide additional continuity between the beams and the columns, and additional moment strength to the beams. Those bars dissipate energy as they yield alternately in tension and compression during an earthquake.A key feature of this syste
33、m is that the grouted bars are deliberately debonded for a short distance in the beam adjacent to the beam-column interface to reduce the high cyclic strains that would otherwise occur at that location. Consequently, during an earthquake, the beams and columns displace essentially as rigid bodies wi
34、th deformations occurring primarily at the beam-column interface as the beam rocks against the column.A second key feature is that post-tensioning allows the columns to be built without the permanent corbels normally found in precast concrete construction. The post-tensioning has two purposes. First
35、, the friction induced by the post-tensioning transfers vertical shears at the interface between beam and column for both gravity and lateral loadings. Second, with the post-tensioning deliberately designed to remain essentially elastic during the DBE, the post-tensioning forces the moment frame to
36、return to its undeformed position following the DBE.R1INTRODUCTION AND SCOPER1.1IntroductionLaboratory studies (Stone et al. 1995; Hawkins and Ishizuka 1988; Priestley 1996; Priestley and MacRae 1994; Palmieri et al. 1996; Nakaki et al. 1999; Priestley et al. 1999; Day 1999) have shown that precast
37、or prestressed concrete moment frames can provide safety and serviceability levels, during and after an earthquake, that meet or exceed performance levels required by 21.1.1.8 of ACI 318-11. To achieve such performance levels, the precast or prestressed concrete moment frames should be carefully pro
38、portioned and detailed. This Standard is based on the studies reported by Stone et al. (1995), Hawkins and Ishizuka (1988), Priestley and MacRae (1994), Priestley (1996), Nakaki et al. (1999), Priestley et al. (1999), and Day (1999). It contains the minimum requirements for ensuring that one type of
39、 precast and prestressed concrete moment frame can sustain a series of oscillations into the inelastic range of response without critical decay in strength or excessive story drifts. Further, that frame should show only minimal or no damage in beam-column joint regions and no permanent displacements
40、 after the oscillations cease.A typical interior frame for this seismic-force-resisting system is illustrated in Fig. R1.1. Details for a vertical longitudinal section of the beam as it passes through the column are shown in Fig. R1.1(b), and details for cross sections of the beam at the column face
41、 (Section B) and on the centerline of the column (Section C) are shown in Fig. R1.1(c). The frame is composed of multistory columns to which single-bay precast concrete beams are connected. Except for possible yielding at the column bases, the interfaces between the precast beams and the continuous
42、columns are the only locations where yielding of the reinforcement (nonlinear action location) occurs in the frame during a major earthquake. Crossing each interface are three deliberately debonded reinforcement elements: post-tensioned strands that extend the full length of the frame in the directi
43、on of its plane; and top and bottom deformed bar energy-dissipating reinforcement that is anchored by grouting in ducts preformed in the beam and column. The length over which the energy-dissipating reinforcement is debonded in the beam adjacent to the connection is selected deliberately to provide
44、the desired design level of overall performance. Cheok et al. (1996) describes the development of a rational basis for the design procedures for a frame with equal strength for the top and bottom partially debonded energy-dissipating reinforcement and central post-tensioning tendons that remain elas
45、tic during a major earthquake. Stanton and Nakaki (2002) describe design guidelines for the same frame system using an iterative step-by-step procedure and displacement-based design procedures. Hawileh et al. (2006) provide nondimensional, noniterative, simplified design procedures for that same sys
46、tem for either displacement-based or force-based design procedures. Where force-based design procedures are used, American Concrete Institute Copyrighted Materialwww.concrete.orgSPECIFICATION FOR UNBONDED PT PRECAST CONCRETE SPECIAL MOMENT FRAMES SATISFYNG ACI 374.1 3CODE COMMENTARYUnder earthquake
47、loading, the special moment frames described in this Standard are intended to behave differently than monolithic frames. Most of the deformations of the frames occur from the opening and closing of the joint at the interface between the precast beam and the column. Consequently, with the detailing p
48、rocedures described in this Standard, damage during a major earthquake is limited in extent, confined essentially to the joint filler material, and is readily repairable after the earthquake. By contrast, monolithic frames designed to Chapter 21 of ACI 318-11 can suffer significant cracking, crushin
49、g, and spalling in the plastic hinging regions of the beam, the beam-column joint, or both, and repair can be costly. Further, monolithic special moment frames designed to Chapter 21 of ACI 318-11 may show permanent lateral deformations following a DBE, whereas the special moment frames described in this Standard do not.The preceding paragraphs define the key characteristics of hybrid frames. The detailing requirements described in this Standard are for one specific type of special hybrid moment frame with:a) Equal moment strengths for the top a
