Concrete Formwork Systems (Civil and Environmental Engineering) (Civil and Environmental Engineering Series, Vol. 2)

318 Pages·1998·1.16 MB·English

by  Awad S. Hanna

Concrete
Formwork
Svstems
-
I -
Awad S. Hanna
University of Wisconsin-Ma dis on
Madison, Wisconsin
Copyright 1999 by Marcel Dekker, Inc. All Rights Reserved.
-
MARCEDL EKKERIN. C NEWY ORK BASEL
DEKKER
Library ofCongress Cataloging-in-PublicationData
Hanna, Awad S.
Concrete formworksystems /byAwad S. Hanna.
p. cm.—(Civiland environmentalengineering series:vol.2)
Includes index.
ISBN 0-8247-0072-4(alk. paper)
1. Concreteconstruction—Formwork. I.Title. II. Series.
TA382.44.H36 1998
624.1′834—dc21 98-37262
CIP
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Civil and Environmental Engineering
ASeriesofReferenceBooksandTextbooks
Editor
Michael D. Meyer
Department of Civil and Environmental Engineering
GeorgiaInstituteofTechnology
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Preface
Formworkdevelopmenthas paralleledthegrowthof concreteconstruc-
tion throughout the 20th century. In the last several decades formwork
technologyhasbecomeincreasinglyimportantinreducingoverallcosts,
sincethestructuralframeconstitutesalargeportionofthecostofaform-
work system.
This book has three objectives. The first is to provide technical
descriptionsandevaluationsoftenformworksystems thatarecurrently
used in concrete construction. The second is to serve as a tool to assist
contractors in selecting the optimal formwork system. The third is to
presentthedesigncriteriaforconventionalformworkforslabsandwalls
using the stress and the stressmodification factors provided by the Na-
tional Design Specifications (NDS) and the American Plywood Associa-
tion (APA).
Followingacomprehensiveintroductorychapter,fivetypesofform-
work systems for concrete slabs are presented in chapters 2–5. These
areconventionalwoodforms,conventionalmetalforms,flyingforms,the
column-mounted shoring system, and tunnel forms. The last four chap-
iv Preface
ters describe five types of formwork systems for concrete columns and
walls: conventional wood forms, ganged forms, jump forms, slip forms,
andself-raisingforms.Particularconsiderationisgiventotopicssuchas
system components, typical work cycles, productivity, and the advan-
tages and disadvantages associated with the use of various systems.
The selectionof aformworksystem is acritical decisionwith very
seriousimplications.Dueconsiderationmustbegiventosuchfactorsas
thesystem’sproductivity,safety,durability,andmanyothervariablesthat
may be specific to the site or job at hand. Chapters 5 and 9 provide a
comparativeanalysis offorming systems for horizontaland verticalcon-
crete work to facilitate the selection of the optimal forming system.
Existingformworkdesignliteratureisinconsistentwiththedesign
criteria for wood provided by the NDS and the APA. Chapters 3 and 7
provide asystematicapproachforformwork design usingthecriteria of
the American Concrete Institute committee 347-94, the NDS, and the
APA.Forinternationalreaders,metric conversionisprovidedintheAp-
pendix.
This book is directed mainly toward construction management,
construction engineering and management students, and concrete con-
tractors. It mayalso serveasausefultext foragraduate courseoncon-
creteformwork,andshouldbeusefulforpracticingengineers,architects,
and researchers.
Awad S. Hanna
Contents
Preface
Acknowledgments
1 Concrete Formwork: An Introduction
1.1 Concrete Construction
1.2 Concrete Formwork
1.3 Formwork Economy and Significance
1.4 An Integrated Concrete/Formwork Life Cycle
1.5 Formwork Materials
2 Horizontal Formwork Systems: Hand-Set Systems
2.1 Horizontal Formwork Systems Classification
2.2 Conventional Wood Formwork System
2.3 Conventional Metal Systems
2.4 Special Horizontal Formwork System
3 Slab Form Design
3.1 Properties of Form Materials
vi Contents
3.2 Properties of Area
3.3 Properties of Sawn Lumber
3.4 Properties of Plywood
3.5 Slab Form Design
3.6 Design Steps
4 Horizontal Formwork Systems: Crane-Set
Systems
4.1 Flying Formwork System
4.2 Column-Mounted Shoring Systems
4.3 Tunnel Formwork System
5 Selection Criteria for Horizontal Formwork
System
5.1 Factors Affecting Horizontal Formwork Selection
5.2 Choosing the Proper Formwork System Using
Tables
6 Vertical Formwork Systems: Crane-Dependent
Systems
6.1 An Introduction to Vertical Formwork Systems
6.2 Conventional Wall/Columns Forming Systems
6.3 Ganged Forming Systems
6.4 Jump Forms
7 Wall Form Design
7.1 Wall Form Components
7.2 Design Loads
7.3 Method of Analysis
7.4 Stresses Calculations
7.5 Determination of Maximum Allowable Span
7.6 Design of Lateral Bracing
8 Vertical Formwork Systems: Crane-Independent
Systems
8.1 Slipforms
8.2 Self-Raising Formwork System
Contents vii
9 Selection Criteria for Vertical Formwork System
9.1 Factors Affecting the Selection of Vertical Formwork
System
9.2 Choosing the Proper Formwork System Using the
Comparison Tables
References
Appendix
Acknowledgments
Igratefullyacknowledgeanumberofindividualswhowereinstrumental
insomewayinthecompletionofthisbook.Ibeginwithmyfriendsand
colleaguesattheUniversityofWisconsin–Madison.Thesupportanden-
couragementofprofessorsJohnBollinger,AlWortley,JeffRussell,Dick
Straub,andGaryBubenzerwillalwaysberemembered.Iwouldlikealso
tothankmystudentsforinspiringmetofurtherexplorethefieldofcon-
crete formwork. Thanks also go to my student Alan Lau, who assisted
in preparing the graphics.
Special thanks go to the many contractors who provided me with
dataandgraphics.Iwouldliketospecificallythanktheeditorialteamof
Marcel Dekker, Inc. for their strong support.
IwouldliketoconveymywarmestthankstomylovingwifePaula
and our son Rewais. It is impossible to describe how supportive Paula
has been throughout the writing of this book. As I spent hundreds of
longhoursatmycomputerpreparingthismanuscript,hernever-ending
loveandsupportinspiredmetokeeppushingon.Mostimportantly,she