TIMBER CONSTRUCTION MANUAL
TIMBERCONSTRUCTION MANUALTimber Construction Manual American Institute of Timber ConstructionCopyright 2012 American Institute of Timber Construction.
TIMBERCONSTRUCTION MANUALSixth EditionAMERICAN INSTITUTE OF TIMBER CONSTRUCTIONJOHN WILEY & SONS, INC.
This book is printed on acid-free paper.Copyright 2012 by American Institute of Timber Construction. All rights reserved.Published by John Wiley & Sons, Inc., Hoboken, New JerseyPublished simultaneously in CanadaNo part of this publication may be reproduced, stored in a retrieval system, or transmitted in anyform or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise,except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, withouteither the prior written permission of the Publisher, or authorization through payment of theappropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA01923, (978) 750-8400, fax (978) 646-8600, or on the web at www.copyright.com. Requests to thePublisher for permission should be addressed to the Permissions Department, John Wiley & Sons,Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011, fax (201) 748-6008, or online atwww.wiley.com/go/permissions.Limit of Liability/Disclaimer of Warranty: While the publisher and the author have used their bestefforts in preparing this book, they make no representations or warranties with respect to theaccuracy or completeness of the contents of this book and specifically disclaim any impliedwarranties of merchantability or fitness for a particular purpose. No warranty may be created orextended by sales representatives or written sales materials. The advice and strategies containedherein may not be suitable for your situation. You should consult with a professional whereappropriate. Neither the publisher nor the author shall be liable for damages arising herefrom.For general information about our other products and services, please contact our Customer CareDepartment within the United States at (800) 762-2974, outside the United States at (317)572-3993 or fax (317) 572-4002.Wiley publishes in a variety of print and electronic formats and by print-on-demand. Some materialincluded with standard print versions of this book may not be included in e-books or inprint-on-demand. If this book refers to media such as a CD or DVD that are not included in theversion you purchased, you may download this material at http://booksupport.wiley.com. For moreinformation about Wiley products, visit www.wiley.com.Library of Congress Cataloging-in-Publication Data:Timber construction manual / American Institute of Timber Construction.—Sixth edition.pages cmIncludes index.ISBN 978-0-470-54509-6 (hardback); 978-1-118-27961-8 (ebk.); 978-1-118-27964-9 (ebk.);978-1-118-27965-6 (ebk.); 978-1-118-27966-3 (ebk.); 978-1-118-27968-7 (ebk.);978-1-118-27973-1 (ebk.)1. Building, Wooden—Handbooks, manuals, etc. I. American Institute of Timber Construction.TA666.T47 2012694—dc232011051084Printed in the United States of America10 9 8 7 6 5 4 3 2 1
CONTENTSPREFACExi1 TIMBER CONSTRUCTION1.11.21.31.41.51.61.71.8Introduction / 1Materials / 1Structural Systems / 13Economy / 27Permanence / 32Seasoning / 37Handling, Storage, and Erection / 38Conclusion / 402 WOOD PROPERTIES2.12.22.32.42.52.62.7142Introduction / 42Specific Gravity and Specific Weight of CommercialLumber Species / 46Dimensional Changes Due to Moistureand Temperature / 50Thermal Insulating Properties / 53Wood in Chemical Environments / 54Acoustical Properties / 55Electrical Properties / 55v
viCONTENTS2.82.9Coefficient of Friction / 56Conclusion / 563 TIMBER DESIGN3.13.23.33.43.53.63.73.8Introduction / 57Loads / 58Design Values / 73Adjustment Factors / 74Deflection / 92Camber / 95Ponding / 98Conclusion / 1004 TIMBER BEAMS4.14.24.34.44.54.64.7134Introduction / 134Column Design Criteria / 134Rectangular Columns / 135Round Columns / 140Tapered Columns / 140Spaced Columns / 141Built-Up Columns / 144Columns with Flanges / 146Tension Members / 147Conclusion / 1486 TIMBER BEAM-COLUMNS AND TENSION BEAMS6.16.2102Introduction / 102Structural Evaluation of Beams / 102Simple Beams / 105Continuous Members / 117Biaxial Bending (Bending about Both Axes) / 122Torsion / 130Conclusion / 1335 TIMBER COLUMNS AND TENSION on / 149General Equation for Beam-Columns / 150149
CONTENTS6.36.46.56.66.76.86.9Centric Axial Compression and Side Load Bending aboutBoth Axes / 156Centric Axial Compression and Side Load Bending aboutStrong Axis Only / 161Eccentric Axial Compression Only / 165Axial Compression Eccentricity in Strong DirectionOnly / 165Columns with Side Brackets / 169Combined Axial Tension and Bending / 170Conclusion / 1737 TAPERED BEAMS7.17.27.37.48.5233Introduction / 233Preliminary Design Procedure / 233Conclusion / 24910 HEAVY TIMBER DECKING10.110.210.310.410.510.6189Introduction / 189Curved Beams with Constant Depth / 195Pitched and Tapered Curved Beams / 200Pitched and Tapered Curved Beams with MechanicallyAttached Haunch / 223Conclusion / 2329 GLULAM ARCHES9.19.29.3174Introduction / 174Tapered Beam Design / 176Beams with Tapered End Cuts / 183Conclusion / 1888 CURVED GLULAM BEAMS8.18.28.38.4viiIntroduction / 251Installation Requirements / 251Design Formulas / 255Section Properties / 256Decking Design Values / 257Conclusion / 259251
viiiCONTENTS11 CONNECTIONS IN TIMBER STRUCTURES11.111.211.311.411.511.6Introduction / 260Connection Detailing Principles / 260Types of Fasteners / 264Reference Design Values for Fasteners / 272Adjustment Factors / 274Conclusion / 28312 MEMBER CAPACITY AT CONNECTIONS12.112.212.312.412.513.5335Introduction / 335Connectors in Side Grain / 336Timber Connectors in End Grain / 347Conclusion / 35215 MOMENT SPLICES15.115.215.315.4309Introduction / 309Dowel-Type Fasteners Loaded Laterally / 309Dowel-Type Fasteners Loaded in Withdrawal / 328Dowel-Type Fasteners Loaded Laterally and inWithdrawal / 330Conclusion / 33414 SHEAR PLATES AND SPLIT RINGS14.114.214.314.4284Introduction / 284Member Capacity at Connections LoadedPerpendicular-to-Grain / 284Member Capacity at Connections LoadedParallel-to-Grain / 291Member Capacity at Connections Loaded at an Angle toGrain / 307Conclusion / 30813 DOWEL-TYPE FASTENERS13.113.213.313.4260Introduction / 353Shear Transfer / 355Moment Transfer / 355Conclusion / 370353
CONTENTS16 LOAD AND RESISTANCE FACTOR DESIGN16.116.216.316.4433Introduction / 433Longitudinal Stringers (Girders) / 436Interconnected Transverse Deck Panels / 447Non-Interconnected Transverse Deck Panels / 447Longitudinal Deck (with Stiffeners) / 457Static Design of Guardrail System / 463Conclusion / 47420 FIRE SAFETY20.120.220.3396Introduction / 396Longitudinal Stringers / 399Transverse Glulam Deck Panels / 418Longitudinal Deck (with Stiffeners) / 425Conclusion / 43219 ASD BRIDGE DESIGN19.119.219.319.419.519.619.7382Introduction / 382Types of Timber Bridges / 383Advantages of Glued Laminated Timber / 389Preservative Treatments / 390Wearing Surfaces / 391Guardrails / 392Design Methods / 393Conclusion / 39518 LRFD BRIDGE DESIGN18.118.218.318.418.5371Introduction / 371Design Values and Adjustment Factors / 372Design Checks / 374Conclusion / 38117 TIMBER ion / 475Types of Construction / 476Lessons from Actual Fires / 476475
xCONTENTS20.420.520.620.720.820.920.10Performance of Wood in Fire / 478Wood versus Steel / 479Heavy Timber Construction / 482Fire-Resistance-Rated Construction / 483Use of Stock Glulam Beams in Fire Rated Construction / 494Fire Retardant Treatment / 495Conclusion / 495APPENDIX ADESIGN EXAMPLES497Introduction / 498APPENDIX BB.1B.2B.3REFERENCE INFORMATION594Beam Diagrams and Formulas / 595Typical Fastener Dimensions and Yield Strengths / 617Structural Glued Laminated Timber Reference DesignValues / 623REFERENCES630INDEX641
PREFACEThe American Institute of Timber Construction (AITC) has developed this TimberConstruction Manual for convenient reference by architects, engineers, contractors, teachers, the laminating and fabricating industry, and all others having aneed for reliable, up-to-date technical data and recommendations on engineeredtimber construction. The information and the recommendations herein are basedon the most reliable technical data available and reflect the commercial practices found to be most practical. Their application results in structurally soundconstruction.The American Institute of Timber Construction, established in 1952, is a nonprofit industry association for the structural glued laminated timber industry. Itsmembers design, manufacture, fabricate, assemble, and erect structural timbersystems utilizing both sawn and structural glued laminated timber components.These systems are used in homes; schools; churches; commercial and industrialbuildings; and for other structures such as bridges, towers, and marine installations. Institute membership also includes engineers, architects, building officials,and associates from other industries related to timber construction.The first edition of the Timber Construction Manual was published in 1966.Changes in the wood products industry, technological advances, and improvements in the structural timber fabricating industry necessitated revisions of theManual . New lumber sizes and revisions in grading requirements for lumberand glued laminated timber were reflected in the second edition published in1974. The third edition was published in 1985 to reflect new information ontimber design methods. The fourth edition of the Manual was published in 1994and contained updated design procedures used for timber construction. The fifthedition (2005) added sections on timber rivet fasteners and load and resistancefactor design.xi
xiiPREFACEThis sixth edition represents a major revision of the format of the Timber Construction Manual . Chapters have been completely restructured for more logicaland complete presentation of information. Long chapters have been divided intosmaller chapters for improved readability and reference.The sixth edition has also been expanded with completely new chapters onglulam arches, LRFD bridge design, fire safety, and moment splices. More than 30new design examples have been added, including an appendix entirely composedof design examples.Preparation of the Timber Construction Manual was guided by the AITCTechnical Advisory Committee and was carried out by AITC staff, the engineersand technical representatives of AITC member firms, and private consultants.Suggestions for the improvement of this manual will be welcomed and willreceive consideration in the preparation of future editions.Although the information herein has been prepared in accordance withrecognized engineering principles and is based on the most accurate andreliable technical data available, it should not be used or relied on for anygeneral or specific application without competent professional examinationand verification of their accuracy, suitability, and applicability by a licensedprofessional engineer, designer, or architect. By the publication of this manual, AITC intends no representation or warranty, expressed or implied, thatthe information contained herein is suitable for any general or specific useor is free from infringement of any patent or copyright. Any user of thisinformation assumes all risk and liability arising from such use.
CHAPTER 1TIMBER CONSTRUCTION1.1INTRODUCTIONThe American Institute of Timber Construction (AITC) has developed this TimberConstruction Manual to provide up-to-date technical information and recommendations on engineered timber construction. Topics of the first chapter includematerials, structural systems, economy, permanence, seasoning, handling, storage,and erection. With an understanding of these topics, the designer can more effectively utilize the advantages of wood construction. Specific design informationand recommendations are covered in subsequent chapters, with accompanyingdesign examples. Supplementary information is provided in appendices.1.2MATERIALSThis manual applies primarily to two types of wood materials—sawn lumberand structural glued laminated timber (glulam). Sawn lumber is the product oflumber mills and is produced from many species. Glued laminated timbers areproduced in laminating plants by adhesively bonding dry lumber, normally of2-in. or 1-in. nominal thickness, under controlled conditions of temperature andpressure. Members with a wide variety of sizes, shapes, and lengths can beproduced having superior strength, stiffness, and appearance. In addition, heavytimber decking, structural panels, and round timbers are also discussed.1.2.1LumberIn its natural state, wood has limited structural usefulness, so it must be converted to a structural form that is compatible with construction needs. The mostTimber Construction Manual American Institute of Timber ConstructionCopyright 2012 American Institute of Timber Construction.1
2TIMBER CONSTRUCTIONcommon structural wood material is sawn lumber. Sawn lumber is also the primary component of structural glued laminated timber. This section will discusscommon growth characteristics of wood and their effects on the properties ofstructural lumber. It will also discuss common grading systems for lumber.1.2.1.1 Lumber Grading As it is sawn from a log, lumber is quite variablein its mechanical properties. Individual pieces may differ in strength by as muchas several hundred percent. For simplicity and economy in use, pieces of lumberof similar quality are classified into various structural grades. The structuralproperties of a particular grade depend on the sorting criteria used, species orspecies group, and other factors.Rules for determining lumber grades are written by rules writing agenciesauthorized by the American Lumber Standards Committee (ALSC) [1]. Foursuch agencies are the Southern Pine Inspection Bureau (SPIB) [2], the West CoastLumber Inspection Bureau (WCLIB) [3], the Western Wood Products Association(WWPA) [4], and the National Lumber Grades Authority (NLGA) [5]. Lumbergrading is also certified by agencies authorized by the American Lumber Standards Committee. Generally, the designer of timber structures is not chargedwith grading but instead with selecting commercially available grades that meetnecessary structural requirements.Lumber rules writing agencies also establish design values and adjustmentfactors for each grade. Design values provided by the agencies are publishedin the National Design Specification (NDS ) [6]. These values and factors aregenerally accepted by model and/or local building codes but are occasionallyadopted with amendments particular to the jurisdiction.Grading is accomplished by sorting pieces according to visually observablecharacteristics (visual grading) or according to measurable mechanical propertiesand visual characteristics (mechanical grading). Both grading methods relate keylumber characteristics to expected strength.1.2.1.2 Characteristics Affecting Structural Lumber Quality Withinany given species of wood, several natural growth characteristics observed instructural lumber are important for the determination of quality of the materialand the assignment of design values. The main characteristics of concern include:specific gravity, knots, slope of grain, and modulus of elasticity. Other importantcharacteristics include reaction wood, juvenile (pith-associated) wood, and compression breaks. Lumber grading rules regulate these characteristics based on theeffect they have on the strength of a piece.1.2.1.2.1 Specific Gravity Specific gravity is a good index for strength andstiffness of clear wood (free of knots and other strength-reducing characteristics). As the specific gravity of wood increases, so do its mechanical properties(strength and stiffness). The specific gravity of certain species of lumber canbe estimated by the amount of latewood in the piece. Because latewood is typically more dense than earlywood, higher proportions of latewood equate to higher
1.2MATERIALS3specific gravities. This relationship is commonly used in grade rules for structurallumber. Visual grading rules classify lumber according to growth ring measurements as having dense, medium, or coarse grain based on the width of the ringsand on the proportion of latewood present. Mechanical grading systems may useweight or calibrated x-ray machines to determine specific gravity.1.2.1.2.2 Knots A knot is formed by sawing through a portion of the treetrunk that formed around a branch. Knots are considered as defects in structural lumber. The presence of a knot disrupts the longitudinal orientation of thewood fibers as they deviate around the knot. A knot may be intergrown withthe surrounding wood or encased by the surrounding wood without intergrownfibers. The latter type of knot is called a loose knot and often falls out, leavinga knothole. Both types of knots reduce the capacity and stiffness of a structuralmember, particularly in tension. Grade rules typically restrict the size, location,and frequency of knots, knot clusters, and knot holes allowed by each grade.1.2.1.2.3 Slope of Grain It is generally desirable to have the longitudinal axisof the wood cells line up with the longitudinal axis of the structural member.However, irregularities in growth and various methods of sawing employed inthe manufacture of structural lumber invariably result in a grain at some angle tothe longitudinal axis of the member. Because wood is orthotropic, wood is notas strong to resist loads at angles to the grain as for loads parallel to the grain.Consequently, lumber grading rules typically restrict the general slope of grainallowed in any particular grade. Additionally, high-grade tension laminationsused in structural glued laminated timber restrict the amount of localized graindeviations, such as those caused by a knot.1.2.1.2.4 Modulus of Elasticity In structural lumber, a correlation has beenobserved between stiffness and other properties. Increases in modulus of elasticityare correlated with increases in specific gravity and strength and with decreasesin slope of grain. The correlation between stiffness and strength forms the basisfor most common mechanical grading systems, which sort pieces by stiffness.1.2.1.2.5 Other Characteristics Reaction wood, timber breaks, juvenilewood, and decay each negatively affect the mechanical and physical propertiesof structural lumber. They are, therefore, limited or excluded by lumbergrade rules.1.2.1.3 Grading Systems Visual grading systems employ trained inspectorsto look at each side of a piece of lumber and assign an appropriate grade based onthe observed characteristics in the piece. Mechanical grading systems use somesort of device to measure properties not apparently visible, such as density ormodulus of elasticity (in addition to visual inspection), to assign grades. Mechanical grading systems may also require random testing of pieces to ensure that theassigned strength and stiffness values are met and maintained over time.
4TIMBER CONSTRUCTIONThree main lumber products are produced from mechanical grading systems inthe United States: machine stress rated (MSR) lumber, mechanically evaluatedlumber (MEL), and E-rated lumber. Pieces graded under the MSR and MELsystems are generally used as individual pieces and are consequently assigneddesign values. E-rating is used primarily for laminating lumber, and design valuesfor individual pieces are not available. Although mechanical grading is increasingin popularity, visual grading remains the most common grading method employedfor structural lumber.1.2.2Structural Glued Laminated TimberThe term structural glued laminated timber refers to an engineered, stress-ratedproduct of a timber laminating plant comprising assemblies of suitably selectedand prepared wood laminations bonded together with ad
The American Institute of Timber Construction, established in 1952, is a non-profit industry association for the structural glued laminated timber industry. Its members design, manufacture, fabricate, assemble, and erect structural timber systems utilizing both sawn and structural glued laminated timber components.
Timber service life design - Design Guide for Durability 06. Timber-framed Construction - Sacrificial Timber Construction Joint 07. Plywood Box Beam Construction for Detached Housing 08. Stairs, Balustrades and Handrails Class 1 Buildings - Construction 09. Timber Flooring - Design Guide for Installation 10. Timber Windows and Doors 11.
N6 Technical Guide Timber Curtain Wall Timber Curtain Wall Technical Guide N7 Timber Curtain Wall Detail Timber Curtain Wall Corner Detail Curtain Wall CL to CL 34 7/8" [887mm] Glass 33 7/8" [861mm] CL to CL 34 7/8" [887mm] Glass 33 7/8" [861mm] F.S. Timber to Timber 103 11/16" [2634mm] Outside Dimension 111 3/8" [2829mm]
Design Guide for Durability #06 Timber-framed Construction - Sacrifi cial Timber Construction Joint #07 Plywood Box Beam Construction for Detached Housing #08 Stairs, Balustrades and Handrails Class 1 Buildings - Construction #09 Timber Flooring - Design Guide for Installation #10 Timber Windows and Doors #11 Noise Transport Corridor Design Guide
1 EN 14081 -1:2005 A1:2011 Timber structures Strength graded structural timber with rectangular cross section Part 1: General requirements 2 EN 14080:2013 Timber structures - Glued laminated timber and glued solid timber - Requirements 3 EN 14374:2004 Timber structures - Structural laminated veneer lumber - Requirements
(SANS 10082) What is a Timber . Correct Standard –SANS 10-082 Timber Frame Construction is not an ABT and timber structures must be built to the SABS standard. Correct treatment is critical H 4 Poles (Piles) at 24 years. Correct Timber Treatment HAZARD CLASS SYMBOL H3 H4 H5 END USE APPLICATION
Timber Piling Council The Timber Piling Council provides technical information, and promotes the use of timber piles in the construction industry. The Timber Piling Council is administered by the Southern Pressure Treater’s Association Photograph shows American Airlines Terminal at JFK w
Pages 10 to 17 of this Datafile present the Timber Species Properties Schedule, a full listing of the poperties of the timber from over 60 species of tree. Species properties may also be modified by special treatments that, for example, increase the decay resistance, surface hardness and dimensional stability of timber products. The wide range of properties available from timber provides the .
Anaesthetic Machine Anatomy O 2 flow-meter N 2 O flow-meter Link 22. Clinical Skills: 27 28 Vaporisers: This is situated on the back bar of the anaesthetic machine downstream of the flowmeter It contains the volatile liquid anaesthetic agent (e.g. isoflurane, sevoflurane). Gas is passed from the flowmeter through the vaporiser. The gas picks up vapour from the vaporiser to deliver to the .
