《ACI-352R-2002.pdf》由会员分享,可在线阅读,更多相关《ACI-352R-2002.pdf(37页珍藏版)》请在三一文库上搜索。
1、ACI 352R-02 supersedes ACI 352R-91(Reapproved 1997) and became effective June 18, 2002. Copyright 2002, 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 mech
2、anical 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. ACI Committee Reports, Guides, Standard Practices, and Commentaries are intend
3、ed for guidance in plan- ning, designing, executing, and inspecting construction. This document is intended for the use of individuals who are competent to evaluate the significance and limita- tions of its content and recommendations and who will accept responsibility for the application of the mat
4、erial 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 therefrom. Reference to this document shall not be made in contract documents. If items found in this document are desir
5、ed 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. 352R-1 Recommendations for Design of Beam-Column Connections in Monolithic Reinforced Concrete Structures ACI 352R-02 Recommendations are giv
6、en for member proportions, confinement of the column core in the joint region, control of joint shear stress, ratio of column- to-beam flexural strength at the connection, development of reinforcing bars, and details of columns and beams framing into the joint. Normal type is used for recommendation
7、s. Commentary is provided in italics to amplify the recommendations and identify available reference material. The recommendations are based on laboratory testing and field studies and provide a state-of-the-art summary of current information. Areas needing research are identified. Design examples a
8、re presented to illustrate the use of the design recommendations. Keywords: anchorage; beam; beam-column; bond; columns; confined concrete; high-strength concrete; joints; reinforced concrete; reinforce- ment; reinforcing steel; shear strength; shear stress. CONTENTS Chapter 1Introduction, scope, an
9、d definitions, p. 352R-2 1.1Introduction 1.2Scope 1.3Definitions Chapter 2Classification of beam-column connections, p. 352R-3 2.1Loading conditions 2.2Connection geometry Chapter 3Design considerations, p. 352R-3 3.1Design forces and resistance 3.2Critical sections 3.3Member flexural strength 3.4Se
10、rviceability Chapter 4Nominal strength and detailing requirements, p. 352R-6 4.1Column longitudinal reinforcement 4.2Joint transverse reinforcement 4.3Joint shear for Type 1 and Type 2 connections 4.4Flexure 4.5Development of reinforcement 4.6Beam transverse reinforcement Reported by Joint ACI-ASCE
11、Committee 352 James R. CagleyJames M. LaFave*Patrick Paultre Marvin E. CriswellDouglas D. LeeM. Saiid Saiidi Catherine E. FrenchRoberto T. LeonBahram M. Shahrooz Luis E. GarciaDonald F. MeinheitJohn W. Wallace T. Russell Gentry*Jack P. MoehleJames K. Wight Theodor KrauthammerStavroula J. Pantazopoul
12、ouLoring A. Wyllie, Jr. Michael E. Kreger* John F. Bonacci* Chair Sergio M. Alcocer Secretary *Member of editorial subcommittee. Chair of editorial subcommittee. 352R-2ACI COMMITTEE REPORT Chapter 5Notation, p. 352R-16 Chapter 6References, p. 352R-16 6.1Referenced standards and reports 6.2Cited refe
13、rences Appendix AAreas needing research, p. 352R-19 A.1Effect of eccentric beams on joints A.2Lightweight aggregate concrete in joints A.3Limit on joint shear A.4Behavior of indeterminate systems A.5Distribution of plastic hinges A.6Innovative joint designs A.7Special joint configurations and loadin
14、gs A.8Joints in existing structures Appendix BDesign examples, p. 352R-20 CHAPTER 1INTRODUCTION, SCOPE, AND DEFINITIONS 1.1Introduction These recommendations are for determining proportions, design, and details of monolithic beam-column connections in cast-in-place concrete frame construction. The r
15、ecom- mendations are written to satisfy strength and ductility requirements related to the function of the connection within a structural frame. This report considers typical beam-column connections in cast-in-place reinforced concrete buildings, as shown in Fig. 1.1. Although the recommendations ar
16、e intended to apply primarily to building structures, they can be extended to other types of frame structures when similar loading and structural conditions exist. Design examples illustrating the use of these recommendations are given in Appendix B. Specifically excluded from these recommendations
17、are slab-column connections, which are the topic of ACI 352.1R, and precast structures where connections are made near the beam-to-column intersection. The material presented herein is an update of a previous report from ACI 352R. Research information available in recent references and Chapter 21 of
18、 ACI 318-02 was reviewed during the updating of these provisions. Modifica- tions have been made to include higher-strength concrete, slab-steel contribution to joint shear, roof-level connections, headed reinforcement used to reduce steel congestion, connections in wide-beam systems, and connection
19、s with eccentric beams. This report addresses connections in both seismic and nonseismic regions, whereas Chapter 21 of ACI 318-02 only addresses connections for seismic regions. A number of recommendations from previous editions of this report have been adopted in Chapter 21 of ACI 318-02 for seism
20、ic design. Recommendations in this report for connec- tions in earthquake-resisting structures are intended to comple- ment those in the 1999 edition of Chapter 21 of ACI 318, covering more specific connection types and providing more detail in some instances. In many designs, column sizes may be de
21、fined by the require- ments of the connection design. Attention is focused on the connection to promote proper structural performance under all loading conditions that may reasonably be expected to occur and to alert the designer to possible reinforcement congestion. 1.2Scope These recommendations a
22、pply only to structures using normalweight concrete with a compressive strength fc not exceeding 15,000 psi (100 MPa) in the connections. From consideration of recent research results of connec- tions with concrete compressive strengths of up to 15,000 psi Fig. 1.1Typical beam-to-column connections
23、(slabs not shown for clarity). Wide-beam cases not shown. BEAM-COLUMN CONNECTIONS IN MONOLITHIC CONCRETE STRUCTURES352R-3 (100 MPa), ACI Committee 352 has extended the limits of the recommendations to include high-strength concrete (Guimaraes, Kreger, and Jirsa 1992; Saqan and Kreger 1998; Sugano et
24、 al. 1991). The committee believes that further research demonstrating the performance and design requirements of connections with lightweight-aggregate concrete is required before the scope of these recommenda- tions can extend beyond normalweight concrete. These recom- mendations are applicable to
25、 structures in which mechanical splices are used, provided that the mechanical splices meet the requirements of Section 21.2.6 of ACI 318-02 and the recom- mendations of the Commentary to Section 21.2.6 of ACI 318-02. 1.3Definitions A beam-column joint is defined as that portion of the column within
26、 the depth of the deepest beam that frames into the column. Throughout this document, the term joint is used to refer to a beam-column joint. A connection is the joint plus the columns, beams, and slab adjacent to the joint. A transverse beam is one that frames into the joint in a direction perpendi
27、cular to that for which the joint shear is being considered. CHAPTER 2CLASSIFICATION OF BEAM-COLUMN CONNECTIONS 2.1Loading conditions Structural connections are classified into two categories Type 1 and Type 2based on the loading conditions for the connection and the anticipated deformations of the
28、connected frame members when resisting lateral loads. 2.1.1 Type 1A Type 1 connection is composed of members designed to satisfy ACI 318-02 strength require- ments, excluding Chapter 21, for members without signifi- cant inelastic deformation. 2.1.2 Type 2In a Type 2 connection, frame members are de
29、signed to have sustained strength under deformation reversals into the inelastic range. The requirements for connections are dependent on the member deformations at the joint implied by the design-loading conditions. Type 1 is a moment-resisting connection designed on the basis of strength in accord
30、ance with ACI 318-02, excluding Chapter 21. Type 2 is a connection that has members that are required to dissipate energy through reversals of deformation into the inelastic range. Connections in moment-resisting frames designed according to ACI 318-02 Sections 21.2.1.3 and 21.2.1.4 are of this cate
31、gory. 2.2Connection geometry 2.2.1 These recommendations apply when the design beam width bb is less than the smaller of 3bc and (bc + 1.5hc), where bc and hc are the column width and depth, respectively. Classification of connections as interior, exterior, or corner connections is summarized in Fig
32、. 1.1. The recom- mendations provide guidance for cases where the beam bars are located within the column core and for cases where beam width is larger than column width, requiring some beam bars to be anchored or to pass outside the column core. Connections for which the beam is wider than the colu
33、mn are classified as wide-beam connections. Test results have given information on the behavior of Type 2 interior (four beams framing into the column) and exterior (three beams framing into the column) wide beam-column connec- tions (Gentry and Wight 1992; Hatamoto, Bessho, and Matsuzaki 1991; Kita
34、yama, Otani, and Aoyama 1987; Kurose et al. 1991; LaFave and Wight 1997; Quintero- Febres and Wight 1997). The maximum beam width allowed recognizes that the effective wide beam width is more closely related to the depth of the column than it is to the depth of the wide beam. The limit is intended t
35、o ensure the complete formation of a beam plastic hinge in Type 2 connections. 2.2.2 These recommendations apply to connections when the beam centerline does not pass through the column centroid, but only when all beam bars are anchored in or pass through the column core. Eccentric connections havin
36、g beam bars that pass outside the column core are excluded because of a lack of research data on the anchorage of such bars in Type 2 connections under large load reversals. CHAPTER 3DESIGN CONSIDERATIONS 3.1Design forces and resistance All connections should be designed according to Chapter 4 for t
37、he most critical combination that results from the inter- action of the multidirectional forces that the members transmit to the joint, including axial load, bending, torsion, and shear. These forces are a consequence of the effects of externally applied loads and creep, shrinkage, temperature, sett
38、lement, or secondary effects. The connection should resist all forces that may be trans- ferred by adjacent members, using those combinations that produce the most severe force distribution at the joint, including the effect of any member eccentricity. Forces arising from deformations due to time-de
39、pendent effects and temperature should be taken into account. For Type 2 connections, the design forces that the members transfer to the joint are not limited to the forces determined from a factored-load analysis, but should be determined from the probable flexural strengths of the members as defin
40、ed in Section 3.3 without using strength-reduction factors. 3.2Critical sections A beam-column joint should be proportioned to resist the forces given in Section 3.1 at the critical sections. The crit- ical sections for transfer of member forces to the connection are at the joint-to-member interface
41、s. Critical sections for shear forces within the joint are defined in Section 4.3.1. Critical sections for bars anchored in the joint are defined in Section 4.5.1. Design recommendations are based on the assumption that the critical sections are immediately adjacent to the joint. Exceptions are made
42、 for joint shear and reinforcement anchorage. Figure 3.1 shows the joint as a free body with forces acting on the critical sections. 3.3Member flexural strength Beam and column flexural strengths are computed for establishing joint shear demand (Section 3.3.4) and for checking the ratio of column-to
43、-beam flexural strength at each connection (Section 4.4). 3.3.1 For Type 1 connections, beam flexural strength should be determined by considering reinforcement in the beam web plus any flange reinforcement in tension in accor- dance with Section 10.6.6 of ACI 318-02. 352R-4ACI COMMITTEE REPORT 3.3.
44、2 For Type 2 connections, wherever integrally cast slab elements are in tension, beam flexural strength should be determined by considering the slab reinforcement within an effective flange width, be, in addition to beam longitu- dinal tension reinforcement within the web. Forces intro- duced to the
45、 joint should be based on beam flexural strength considering the effective slab reinforcement contribution for negative bending moment (slab in tension). Slab reinforcement should be considered to act as beam tension reinforcement having strain equal to that occurring in the web at the depth of the
46、slab steel. Only continuous or anchored slab reinforcement should be considered to contribute to the beam flexural strength. Except for the case of exterior and corner connections without transverse beams, the effective tension flange width be should be taken the same as that prescribed in ACI 318-
47、02 for flanges in compression. Section 8.10.2 of ACI 318-02 should be used for beams with slabs on both sides. Section 8.10.3 of ACI 318-02 should be used for beams with slabs on one side only. The effective slab width should not be taken less than 2bb, where bb is the web width of the beam. In the
48、case of exterior connections without transverse beams, slab reinforcement within an effective width 2ct + bc centered on the column should be considered to contribute to the flexural strength of the beam with tension flange(s). For corner connections without transverse beams, the effective slab widt
49、h be should be taken as (ct + bc) plus the smaller of ct and the perpendicular distance from the side face of the column to the edge of the slab parallel to the beam. The quantity ct is a width of slab in the transverse direction equal to the distance from the interior face of the column to the slab edge measured in the longitudinal direction, but not exceeding the total depth of the column in the longitudinal direction hc. The effective slab width for exterior and corner connections without transverse beams need not be taken as more than 1
链接地址:https://www.31doc.com/p-3728214.html