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1、ACI 360R-06 supersedes 360R-92 (Reapproved 1997) and became effective August 9, 2006. Copyright 2006, 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 mechan
2、ical device, printed, written, or oral, or recording for sound or visual reproduction or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors. 360R-1 ACI Committee Reports, Guides, Standard Practices, and Commentaries are int
3、ended 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 limitations of its content and recommendations and who will accept responsibility for the application of the mate
4、rial 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 desire
5、d 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. Design of Slabs-on-Ground Reported by ACI Committee 360 ACI 360R-06 This document presents information on the design of slabs-on-ground, prima
6、rily industrial floors. The report addresses the planning, design, and detailing of slabs. Background information on design theories is followed by discussion of the types of slabs, soil-support systems, loadings, and jointing. Design methods are given for unreinforced concrete, reinforced concrete,
7、 shrinkage-compensating concrete, post-tensioned concrete, fiber- reinforced concrete slabs-on-ground, and slabs-on-ground in refrigerated buildings, followed by information on shrinkage and curling problems. Advantages and disadvantages of each of these slab designs are provided, including the abil
8、ity of some slab designs to minimize cracking and curling more than others. Even with the best slab designs and proper construction, however, it is unrealistic to expect crack-free and curl-free floors. Conse- quently, every owner should be advised by both the designer and contrac- tor that it is no
9、rmal to expect some amount of cracking and curling on every project, and that such occurrence does not necessarily reflect adversely on either the adequacy of the floors design or the quality of its construction. Design examples appear in an appendix. Keywords: concrete; curling; design; floors-on-g
10、round; grade floors; industrial floors; joints; load types; post-tensioned concrete; reinforcement (steel, fibers); shrinkage; shrinkage-compensating; slabs; slabs-on-ground; soil mechanics; shrinkage; warping. CONTENTS Chapter 1Introduction, p. 360R-3 1.1Purpose and scope 1.2Work of Committee 360 a
11、nd other relevant committees 1.3Work of non-ACI organizations 1.4Design theories for slabs-on-ground 1.5Overview of subsequent chapters 1.6Further research Chapter 2Slab types, p. 360R-5 2.1 Introduction 2.2 Slab types 2.3General comparison of slab types 2.4Design and construction variables 2.5Concl
12、usion Chapter 3Support systems for slabs-on-ground, p. 360R-7 3.1Introduction 3.2Geotechnical engineering reports 3.3Subgrade classification 3.4Modulus of subgrade reaction 3.5Design of slab-support system 3.6Site preparation 3.7Inspection and site testing of slab support 3.8Special slab-on-ground s
13、upport problems J. Howard AllredBarry E. ForemanJoseph F. Neuber, Jr.A. Fattah Shaikh Carl BimelTerry J. FricksRussell E. NeudeckRichard E. Smith Joseph A. BohinskyPatrick J. HarrisonScott L. NiemitaloScott M. Tarr William J. BrickeyJerry A. Holland*Nigel K. ParkesR. Gregory Taylor Joseph P. Buongio
14、rnoPaul B. LafontaineRoy H. ReitermanEldon G. Tipping Allen FaceSteven N. MetzgerJohn W. RohrerWayne W. Walker C. Rick FelderJohn P. Munday *Chair of ACI 360 who served during a portion of the time required to create this document. The committee would also like to acknowledge Miroslav Vejvoda for hi
15、s contributions as Chair of the Prestressing Subcommittee and Roy Leonard (deceased) for his work on soil support systems. Arthur W. McKinney Chair Robert B. Anderson Vice Chair Philip Brandt Secretary 360R-2ACI COMMITTEE REPORT Chapter 4Loads, p. 360R-17 4.1Introduction 4.2Vehicular loads 4.3Concen
16、trated loads 4.4Distributed loads 4.5Line and strip loads 4.6Unusual loads 4.7Construction loads 4.8Environmental factors 4.9Factors of safety Chapter 5Joints, p. 360R-21 5.1Introduction 5.2Load-transfer mechanisms 5.3Sawcut contraction joints 5.4Joint protection 5.5Joint filling and sealing Chapter
17、 6Design of unreinforced concrete slabs, p. 360R-29 6.1Introduction 6.2Thickness design methods 6.3Shear transfer at joints 6.4Maximum joint spacing Chapter 7Design of slabs reinforced for crack- width control, p. 360R-32 7.1Introduction 7.2Thickness design methods 7.3Reinforcement for crack-width c
18、ontrol only 7.4Reinforcement for moment capacity 7.5Reinforcement location Chapter 8Design of shrinkage-compensating concrete slabs, p. 360R-32 8.1Introduction 8.2Thickness determination 8.3Reinforcement 8.4Other considerations Chapter 9Design of post-tensioned slabs-on- ground, p. 360R-36 9.1Notati
19、on 9.2Definitions 9.3Introduction 9.4Applicable design procedures 9.5Slabs post-tensioned for crack control 9.6Industrial slabs with post-tensioned reinforcement for structural support 9.7Residential slabs with post-tensioned reinforcement for structural action 9.8Design for slabs on expansive soils
20、 9.9Design for slabs on compressible soil Chapter 10Fiber-reinforced concrete slabs-on- ground, p. 360R-45 10.1Introduction 10.2Polymeric fiber reinforcement 10.3Steel fiber reinforcement Chapter 11Structural slabs-on-ground supporting building code loads, p. 360R-48 11.1Introduction 11.2Design cons
21、iderations Chapter 12Design of slabs for refrigerated facilities, p. 360R-49 12.1Introduction 12.2Design and specification considerations 12.3Temperature drawdown Chapter 13Reducing effects of slab shrinkage and curling, p. 360R-50 13.1Introduction 13.2Drying and thermal shrinkage 13.3Curling and wa
22、rping 13.4Factors that affect shrinkage and curling 13.5Compressive strength and shrinkage 13.6Compressive strength and abrasion resistance 13.7Removing restraints to shrinkage 13.8Base and vapor retarders/barriers 13.9Distributed reinforcement to reduce curling and number of joints 13.10Thickened e
23、dges to reduce curling 13.11Relation between curing and curling 13.12Warping stresses in relation to joint spacing 13.13Warping stresses and deformation 13.14Effect of eliminating sawcut contraction joints with post-tensioning or shrinkage-compensating concrete 13.15Summary and conclusions Chapter 1
24、4References, p. 360R-57 14.1Referenced standards and reports 14.2Cited references APPENDIX Appendix 1Design examples using PCA method, p. 360R-61 A1.1Introduction A1.2PCA thickness design for single-axle load A1.3PCA thickness design for slab with post loading A1.4Other PCA design information Append
25、ix 2Slab thickness design by WRI method, p. 360R-63 A2.1Introduction A2.2WRI thickness selection for single-axle wheel load A2.3WRI thickness selection for aisle moment due to uniform loading Appendix 3Design examples using COE charts, p. 360R-64 A3.1Introduction A3.2Vehicle wheel loading A3.3Heavy
26、forklift loading Appendix 4Slab design using post-tensioning, p. 360R-67 A4.1Design example: Residential slabs on expansive soil DESIGN OF SLABS-ON-GROUND360R-3 A4.2Design example: Using post-tensioning to minimize cracking A4.3Design example: Equivalent tensile stress design Appendix 5Examples usin
27、g shrinkage- compensating concrete, p. 360R-72 A5.1Introduction A5.2Example with amount of steel and slab joint spacing predetermined Appendix 6Design examples for steel FRC slabs-on-ground using yield line method, p. 360R-72 A6.1Introduction A6.2Assumptions/design criteria Conversion factors, p. 36
28、0R-74 CHAPTER 1INTRODUCTION 1.1Purpose and scope This guide presents state-of-the-art information on the design of slabs-on-ground. Design is defined as the decision- making process of planning, sizing, detailing, and developing specifications preceding construction of slabs-on-ground. Information o
29、n other aspects, such as materials, construction methods, placement of concrete, and finishing techniques, is included only where it is needed in making design decisions. In the context of this guide, slab-on-ground is defined as: a slab, supported by ground, whose main purpose is to support the app
30、lied loads by bearing on the ground. The slab may be of uniform or variable thickness, and it may include stiffening elements such as ribs or beams. The slab may be unreinforced, reinforced, or post-tensioned concrete. The reinforcement steel may be provided to limit the crack widths resulting from
31、shrinkage and temperature restraint and the applied loads. Post-tensioning steel may be provided to minimize cracking due to shrinkage and temperature restraint and to resist the applied loads. This guide covers the design of slabs-on-ground for loads from material stored directly on the slab, stora
32、ge rack loads, and static and dynamic loads associated with equipment and vehicles. Other loads, such as loads on the roof transferred through dual-purpose rack systems, are also mentioned. In addition to design, this guide discusses soil-support systems; shrinkage and temperature effects; cracking,
33、 curling or warping; and other concerns affecting slab design. Although the same general principles are applicable, this guide does not specifically address the design of roadway pavements, airport pavements, parking lots, and mat foundations. 1.2Work of ACI Committee 360 and other relevant committe
34、es 1.2.1 ACI Committee 360 develops and reports on criteria for design of slabs-on-ground, with the exception of highway and airport pavements, parking lots, and mat foundations. 1.2.2 ACI Committee 302 develops recommendations for construction of slab-on-ground and suspended-slab floors for industr
35、ial, commercial, and institutional buildings. ACI 302.1R provides guidelines and recommendations on materials and slab construction. 1.2.3 ACI Committee 223 develops recommendations on the use of shrinkage-compensating concrete. 1.2.4 ACI Committee 325 addresses the structural design, construction,
36、maintenance, and rehabilitation of concrete pavements. 1.2.5 ACI Committee 332 develops information on the use of concrete for one- and two-family dwellings and multiple single-family dwellings not more than three stories in height as well as accessory structures (residential). Where a residential s
37、lab-on-ground is placed, only loadings from pedestrian and passenger vehicles are expected. The slab should be continuously supported throughout and placed on suitable soil or controlled fill where little volume change is expected. Where these conditions are not met, a residential slab-on-ground sho
38、uld be designed specifically for the application. 1.2.6 ACI Committee 336 addresses design and related considerations of foundations that support and transmit substantial loads from one or more structural members. The design procedures for mat foundations are given in ACI 336.2R. Mat foundations are
39、 typically more rigid and more heavily reinforced than common slabs-on-ground. 1.2.7 ACI Committee 330 monitors developments and prepares recommendations on design, construction, and maintenance of concrete parking lots. Parking lot pavements have unique considerations that are covered in ACI 330R,
40、which includes design and construction- and discussions on material specifications, durability, maintenance, and repair. 1.2.8 ACI Committee 544 provides measurement of properties of fiber-reinforced concrete (FRC); a guide for specifying proportioning, mixing, placing, and finishing steel FRC; and
41、design considerations for steel FRC. 1.3Work of non-ACI organizations Numerous contributions of slabs-on-ground come from organizations and individuals outside the American Concrete Institute. The U.S. Army Corps of Engineers (USACE), the National Academy of Science, and the Department of Housing an
42、d Urban Development (HUD) have developed guidelines for floor slab design and construction. Several industrial asso- ciations, such as the Portland Cement Association (PCA), Wire Reinforcement Institute (WRI), Concrete Reinforcing Steel Institute (CRSI), Post-Tensioning Institute (PTI), as well as s
43、everal universities and consulting engineers have studied slabs-on-ground and developed recommendations on their design and construction. In addition, periodicals such as Concrete International and Concrete Construction have continuously disseminated information for the use of those involved with sl
44、abs-on-ground. 1.4Design theories for slabs-on-ground 1.4.1 IntroductionStresses in slabs-on-ground result from both applied loads and volume changes of the soil and concrete. The magnitude of these stresses depends on factors such as the degree of continuity, subgrade strength and uniformity, metho
45、d of construction, quality of construction, 360R-4 ACI COMMITTEE REPORT and magnitude and position of the loads. In most cases, the effects of these factors can only be evaluated by making simplifying assumptions with respect to material properties and soil-structure interaction. The following secti
46、ons briefly review some of the theories that have been proposed for the design of soil-supported concrete slabs. 1.4.2 Review of classical design theoriesThe design methods for slabs-on-ground are based on theories originally developed for airport and highway pavements. An early attempt at a rationa
47、l approach to design was made around 1920, when Westergaard (1926) proposed the so-called “corner formula” for stresses. Although the observations in the first road test with rigid pavements seemed to be in agreement with the predictions of this formula, its use has been limited. Westergaard develop
48、ed one of the first rigorous theories of structural behavior of rigid pavement in the 1920s (Westergaard 1923, 1925, 1926). This theory considers a homogeneous, isotropic, and elastic slab resting on an ideal subgrade that exerts, at all points, a vertical reactive pressure proportional to the defle
49、ction of the slab. This is known as a Winkler subgrade (Winkler 1867). The subgrade acts as a linear spring, with a proportionality constant k with units of pres- sure (lb/in.2 kPa) per unit deformation (in. m). The units are commonly abbreviated as lb/in.3 (kN/m3). This is the constant now recognized as the coefficient (or modulus) of subgrade reaction. Extensive investigations of structural behavior of concrete pavement slabs performed in the 1930s at the Arlin
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