1、FORMWORK FOR CONCRETEFORMWORK FOR CONCRETE Eighth Edition DAVID W. JOHNSTON Edward I. Weisiger Distinguished Professor Emeritus North Carolina State University Prepared with the assistance of ACI COMMITTEE 347, FORMWORK FOR CONCRETE Kenneth L. Berndt, Chair Matthew J. Poisel, Secretary Rodney D. Ada
2、ms Mary Bordner-Tanck George Charitou Eamonn F. Connolly James N. Cornell II Jack L. David Aubrey L. Dunham Jeffrey C. Erson N. John Gardner Brian J. Golanowski Timothy Hayes G. P . Jum Horst Jeffrey C. Jack David W. Johnston Roger S. Johnston Robert G. Kent Kevin R. Koogle Jim Kretz H. S. Lew Rober
3、t G. McCracken Eric S. Peterson Steffen Pippig Douglas J. Schoonover Aviad Shapira John M. Simpson Rolf A. Spahr Pericles C. Stivaros Daniel B. Toon Ralph H. TulisFormwork for Concrete 8 thEdition First Printing: August 2014 Second Printing: December 2014 Errata changes as of October 13, 2015 Printe
4、d in Chelsea, Michigan ISBN 978-0-87031-912-9 Copyright 2014 by the American Concrete Institute. All rights reserved. This eighth edition has been revised to agree with “Guide to Formwork for Concrete (ACI 347R-14), ” which is reprinted in full in the appendix. Other revisions have been made for con
5、sistency with ACI documents undergoing revision since previous editions of this manual were issued. Wood design stresses and procedures have been updated to agree with the 2012 National Design Specification issued by the American Wood Council. ” The drawings and examples in this book are based on ty
6、pical designs and should not be used as working drawings or in place of making calculations for a particular project. They are intended to be helpful in the preparation of complete formwork plans that should be adapted to local conditions and comply with all applicable legal requirements. In no way
7、is this book able to, or intended to, supplant the qualified designer or engineer to whom formwork should be entrusted. Limitations of space and time make it impossible to show all of the methods, materials, and products available for formwork construction. Omission of any item therefore should not
8、be regarded as a judgment that it is inferior or unsuitable. Managing Editor: Michael Tholen, Ph.D., P .E. Art Program: Claire Hiltz Manager, Publishing Services: Barry Bergin Production Editors: Carl Bischof, Kelli Slayden, Ashley Poirier, Kaitlyn Hinman Page Design & Composition: Ryan Jay Cover, A
9、cknowledgements, and Foreword art courtesy Eric Peterson Manufacturing: Marie Fuller American Concrete Institute 38800 Country Club Drive Farmington Hills, MI 48331 USA www.concrete.orgv DEDICATION The eighth edition of Formwork for Concrete is dedicated to the memory and achieve- ments of M. K. Hur
10、d, author of the first seven editions and constant advocate for safety, economy, and quality of formwork. Mary Hurd (1926-2013), a civil engineering graduate of Iowa State University, began her career as a staff engineer with the American Concrete Institute in 1947. In the early 1960s, she was asked
11、 by ACI to work with the committee on Formwork for Concrete to develop a major publication on formwork that had been identified as an industry need. Over the years, as she moved at various times from ACI staff engineer to private consultant or editor of concrete industry publications, she was repeat
12、edly engaged by ACI to update Formwork for Concrete. Well known and respected as an engineering writer and editor on concrete construction, formwork, and concrete aesthetics, she published over 230 articles on always-timely topics. In the five decades since Formwork for Concrete made its first appea
13、rance, more than 130,000 copies have been printed and the book has become recognized as the “green bible” of the formwork industry. Formwork for Concrete has been and continues to be a cooperative effort supported by individuals, companies, public agencies, and industry and professional associations
14、 in large measure due to the groundwork laid and respect for Formwork for Concrete garnered through the pioneering efforts of Mary Hurd. Mary K. Hurd in 1969vi ACKNOWLEDGMENTS The American Concrete Institute would like to acknowledge the hard work and support of several groups and individuals withou
15、t whom the production of a document of this caliber would not be possible. Without the vision and effort put forth by Mary K. Hurd and the members of ACI Committee 347 over the last 50 years, much of the basis for this document would not exist. Their work has established Formwork for Concrete as a w
16、ell-known and respected reference in the concrete formwork industry and as an excellent teaching resource in classrooms across the United States. David W. Johnston, Ph.D., P .E., took on the task of revising and bringing an iconic docu- ment up-to-date by including the latest design standards, desig
17、n methods, procedures, products, and several new worked examples. In addition, he coordinated the selection of nearly 500 modern color photographs to enable the eighth edition of Formwork for Concrete to be the first edition in full color. Photos in this manual without photo credit were provided by
18、Dr. Johnston. The assistance of Matthew Poisel in revising the document is also gratefully acknowledged. The assistance of the many formwork and construction companies that permitted the use of their photographs and illustrations allows Formwork for Concrete to show a breadth of formwork application
19、 that would not be possible otherwise. Specific acknowledgments for their contributions are found in the figure captions. Members of ACI Committee 347, Formwork for Concrete, were engaged by the author during the process of revising the document, as they have been during the development of previous
20、editions. Their comments and insight have brought a balanced viewpoint to the document that is not found in other documents on the topic. Members of the ACI Educational Activities Committee (EAC), with the assistance of outside reviewers selected from ACI Committee 347, provided final review comment
21、s for chapters of the document. Responses by the author to these comments were reviewed and approved by the EAC members who commented on the chapter. These comments provided a fresh perspective and helped ensure that people reading the document for the first time would be able to quickly and easily
22、understand the content. These reviewers also made sure that the content of this work was consistent with other ACI documents. These suggestions have helped improve the document for the final end user. Michael Tholen, Ph.D., P .E. Managing Editorvii FOREWORD Following in the footsteps of Mary K. Hurd
23、 is a challenge. My respect for her knowledge of formwork included recent decades of interaction with her on ACI Committee 347, but also extended back to my days as a student specializing in construction engineering and structural engineering. In 1965, I encountered the first edition of Formwork for
24、 Concrete as a construction engineering undergraduate student at North Carolina State Univer- sity. During my years in industry and later as a faculty member, my appreciation of her pioneering and dedicated work on Formwork for Concrete and her contributions to ACI Committee 347 continued to grow. T
25、he eighth edition, as all previous editions, follows the most recent guidelines estab- lished by ACI Committee 347 and documented in the committee report, now ACI 347R- 14, which is reprinted in full in the appendix. This new edition of Formwork for Concrete considers the updated lateral pressure pr
26、ovisions now provided by ACI 347. Expanded coverage is provided for wind loads, analysis of the shoring and reshoring process, evaluation of concrete and structure strength to withstand shoring loads, and design of shoring and bracing elements. This edition also reflects the latest changes in wood d
27、esign recommendations of the American Wood Council and introduces LRFD in addition to the primary coverage based on ASD procedures. The recent recommendations of other ACI committees have also been considered in the manual revisions and some related provi- sions of ACI 318 and OSHA have been extract
28、ed for convenient reference in the appendix. The growing number of standards related to design of the construction process and design of temporary structures, as well as a number of formwork industry products and practices adopted since the last edition was published, have been considered during dev
29、elopment of the revisions. For instructional use, a series of problems and review ques- tions have been provided following the appendix. Drafts of revisions have been submitted for review and comment by members of ACI Committee 347, whose suggestions and advice have been most constructive. I am very
30、 grateful to the many committee members who shared their expertise and counsel during the preparation of the eighth edition. My special thanks to colleague Matthew Poisel, for his development of the data for the span tables of Chapter 9. The author is also grateful to the many individuals and organi
31、zations who have contributed nearly 500 new illustra- tions, drawings, and photo images to this first edition to be printed in color and to the many contractors who have provided access to their construction sites for photographs by the author, particularly United Forming, Inc., and Clancy & Theys C
32、onstruction Co. David W. Johnston, Ph.D., P .E. July 2014viii Chapters 1: INTRODUCTION 2: GENERAL OBJECTIVES IN FORMWORK BUILDING 3: OVERALL PLANNING 4: MATERIALS, ACCESSORIES, AND PROPRIETARY PRODUCTS 5: LOADS AND PRESSURES 6: SHORING AND FLOOR LOADS IN MULTI-STORY STRUCTURES 7: DESIGN OF SLAB, WAL
33、L, BEAM, AND COLUMN FORMS 8: DESIGN OF FORM SHORES AND BRACING 9: DESIGN TABLES 10: FORMWORK DRAWINGS 11: BUILDING AND ERECTING THE FORMWORK 12: USING THE FORMS 13: FORMED CONCRETE SURFACE QUALITY 14: FORMWORK FOR ARCHITECTURAL CONCRETE 15: BRIDGE FORMWORK 16: MASS CONCRETE FORMWORK 17: TUNNEL AND S
34、HAFT FORMWORK 18: SPECIAL TECHNIQUES IN CONCRETE CONSTRUCTION APPENDIX AREFERENCED STANDARDS AND REPORTS APPENDIX BNOTATION APPENDIX CGLOSSARY APPENDIX DCONVERSIONS APPENDIX EACI 347R-14 GUIDE APPENDIX FACI 318-11 CODE AND COMMENTARY APPENDIX GOSHA REGULATIONS APPENDIX HPROBLEMS INDEXix CONTENTS 1:
35、INTRODUCTION 2: GENERAL OBJECTIVES IN FORMWORK BUILDING 2.1 Standards, Specifications, and Guides Related to Formwork 2-1 2.1.1 Regulations for Safety 2-1 2.1.2 Project Specifications for Quality 2-2 2.1.3 Guides and Specifications for Formwork Design and Construction 2-2 2.2 How Formwork Affects Co
36、ncrete Quality 2-3 2.3 Planning for Safety 2-3 2.3.1 Supervision and Inspection 2-3 2.3.2 Platforms and Access for Workers 2-3 2.3.3 Control of Concreting Practices 2-4 2.3.4 Improving Soil Bearing and Bracing 2-4 2.3.5 Shoring and Reshoring 2-4 2.4 Causes of Failures 2-5 2.4.1 Improper Stripping an
37、d Shore Removal 2-5 2.4.2 Inadequate Bracing 2-6 2.4.3 Inadequate Concrete Strength Development 2-6 2.4.4 Vibration and Impact 2-6 2.4.5 Unstable Soil under Mudsills, Shoring Not Plumb 2-8 2.4.6 Inadequate Control of Concrete Placement 2-8 2.4.7 When Formwork Is Not at Fault 2-8 2.4.8 Lack of Attent
38、ion to Formwork Details 2-10 2.5 Relationship of Architect, Engineer, and Contractor 2-10 2.5.1 Defining the Concrete Structure 2-10 2.5.2 Maintaining and Coordinating Tolerances 2-11 2.5.3 Preparing a Formwork Specification 2-11 2.5.4 Design, Inspection, and Approval of Formwork 2-12 2.5.5 Complex
39、Structures 2-12 2.5.6 Stay-in-Place Forms 2-12 2.5.7 Composite Construction 2-12 2.5.8 Stripping and Decentering 2-12 2.5.9 Materials and Accessories Related to Formed Surface of Exposed Concrete 2-13 2.6 Achieving Economy of Formwork 2-13 2.6.1 Measurement and Payment for Formwork 2-14 2.6.2 How th
40、e Engineer/Architect Can Reduce Form Costs 2-14 3: OVERALL PLANNING 3.1 Development of a Basic System 3-1 3.1.1 Compare Alternate Methods 3-2 3.1.2 Examine Form Plan in Relation to Total Job 3-2 3.2 Key Areas of Cost Reduction 3-2 3.3 Planning for Maximum Reuse 3-3 3.3.1 Developing a Practical Reuse
41、 Plan 3-4 3.3.2 Comparing Reuse Schemes 3-4x 3.4 Economical Form Construction 3-4 3.4.1 Job-Built Forms 3-4 3.4.2 Purchased or Rented Forms 3-6 3.5 Setting, Stripping, and Cycling Costs 3-6 3.6 Other Costs Affected by the Formwork Plan 3-7 3.6.1 Crew Efficiency 3-7 3.6.2 Cranes and Hoists 3-8 3.7 Fo
42、rmwork Planning Process 3-8 3.8 BIM for Planning Formwork Operations 3-13 3.8.1 How BIM is Used by a Formwork Contractor 3-13 3.8.2 Advantages of BIM 3-15 4: MATERIALS, ACCESSORIES, AND PROPRIETARY PRODUCTS 4.1 Lumber 4-1 4.1.1 Kinds of Lumber 4-2 4.1.2 Lumber Finish and Sizes 4-3 4.1.3 Stress Gradi
43、ng and Design Values 4-4 4.1.4 Adjustment Factors for Sawn Lumber Design Values 4-6 4.2 Engineered Wood Products 4-8 4.2.1 Glued Laminated Timber 4-9 4.2.2 Structural Composite Lumber 4-10 4.2.3 I-Joists 4-11 4.2.4 Wood Trusses 4-11 4.3 Plywood 4-11 4.3.1 Construction and Sizes Available 4-12 4.3.2
44、Types and Grades 4-12 4.3.3 Overlaid Plywood 4-14 4.3.4 Textured Surfaces 4-15 4.3.5 Strength Properties 4-15 4.3.6 Bending Plywood to Curved Surfaces 4-15 4.4 Other Framing and Facing Materials 4-16 4.4.1 Reconstituted Wood Materials 4-16 4.4.2 Steel 4-16 4.4.3 Aluminum 4-17 4.4.4 Glass Fiber-Reinf
45、orced Polymer 4-18 4.4.5 Other Polymeric Form Materials 4-18 4.4.6 Fabric and Porous Forms 4-19 4.4.7 Form Lining Materials 4-20 4.4.8 Insulation and Insulating Forms 4-22 4.5 Hardware and Fasteners 4-23 4.5.1 Nails 4-23 4.5.2 Wood Screws 4-26 4.5.3 Bolts, Lag Screws, and Other Connectors 4-28 4.5.4
46、 Ties 4-31 4.5.5 Anchors 4-35 4.5.6 Hangers 4-36 4.5.7 Friction Collars and Support Brackets 4-36xi 4.5.8 Spacers and Spreaders 4-37 4.5.9 Steel Strapping 4-37 4.5.10 Column Clamps 4-38 4.6 Prefabricated Forms 4-38 4.6.1 Panel Forms and Forming Systems 4-38 4.6.2 Pans and Domes for Concrete Joist Co
47、nstruction 4-39 4.6.3 Void and Duct Forms 4-40 4.6.4 Column Forms 4-41 4.6.5 Stay-In-Place Forms 4-42 4.6.6 Special Purpose and Custom-Made Forms 4-43 4.7 Shoring 4-43 4.7.1 Single-Post Shores 4-44 4.7.2 Shoring Frames 4-44 5: LOADS AND PRESSURES 5.1 Notation for Loads and Pressures 5-1 5.2 Load Com
48、binations 5-2 5.2.1 ASD Combinations 5-2 5.2.2 LRFD Combinations 5-2 5.3 Vertical Loads 5-3 5.3.1 Dead Loads 5-3 5.3.2 Live Loads 5-4 5.4 Lateral Pressure of Fresh Concrete 5-4 5.4.1 Factors Affecting Lateral Pressure 5-6 5.4.2 History of Lateral Pressure Values for Form Design 5-7 5.4.3 Lateral pre
49、ssure of concrete equations 5-8 5.4.4 Bottom-Up Pumping of Concrete 5-9 5.4.5 Column Forms 5-10 5.4.6 Wall Forms 5-10 5.4.7 Pressure on Sloping Surfaces 5-11 5.5 Horizontal Loads 5-13 5.5.1 Minimum Horizontal Loads 5-13 5.5.2 Wind Loads 5-14 5.5.3 Shielding from Wind Pressure 5-17 5.5.4 Design Wind Load 5-18 5.5.5 Wind Load on Wall and Column Forms 5-18 5.5.6 Wind Loads on Elevated Slab Formwork 5-19 5.5.7 Starting and Stopping Equipment Loads 5-20 5.5.8 Seismic Loads 5-20 5.6 Other Loads 5-20 6: SHORING AND FLOOR LOADS IN MULTI-STORY STRUCTURES 6.1 Shoring of Multi-story Concrete S
