Timber construction manual

658 Pages·2012·5.62 MB·English

TIMBER
CONSTRUCTION MANUAL
Timber Construction Manual American Institute of Timber Construction
Copyright © 2012 American Institute of Timber Construction.
TIMBER
CONSTRUCTION MANUAL
Sixth Edition
AMERICAN INSTITUTE OF TIMBER CONSTRUCTION
JOHNWILEY&SONS,INC.
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LibraryofCongressCataloging-in-PublicationData:
Timberconstructionmanual/AmericanInstituteofTimberConstruction.—Sixthedition.
pagescm
Includesindex.
ISBN978-0-470-54509-6(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.AmericanInstituteofTimberConstruction.
TA666.T472012
694—dc23
2011051084
PrintedintheUnitedStatesofAmerica
10987654321
CONTENTS
PREFACE xi
1 TIMBERCONSTRUCTION 1
1.1 Introduction / 1
1.2 Materials / 1
1.3 Structural Systems / 13
1.4 Economy / 27
1.5 Permanence / 32
1.6 Seasoning / 37
1.7 Handling, Storage, and Erection / 38
1.8 Conclusion / 40
2 WOODPROPERTIES 42
2.1 Introduction / 42
2.2 Specific Gravity and Specific Weight of Commercial
Lumber Species / 46
2.3 Dimensional Changes Due to Moisture
and Temperature / 50
2.4 Thermal Insulating Properties / 53
2.5 Wood in Chemical Environments / 54
2.6 Acoustical Properties / 55
2.7 Electrical Properties / 55
v
vi CONTENTS
2.8 Coefficient of Friction / 56
2.9 Conclusion / 56
3 TIMBERDESIGN 57
3.1 Introduction / 57
3.2 Loads / 58
3.3 Design Values / 73
3.4 Adjustment Factors / 74
3.5 Deflection / 92
3.6 Camber / 95
3.7 Ponding / 98
3.8 Conclusion / 100
4 TIMBERBEAMS 102
4.1 Introduction / 102
4.2 Structural Evaluation of Beams / 102
4.3 Simple Beams / 105
4.4 Continuous Members / 117
4.5 Biaxial Bending (Bending about Both Axes) / 122
4.6 Torsion / 130
4.7 Conclusion / 133
5 TIMBERCOLUMNSANDTENSIONMEMBERS 134
5.1 Introduction / 134
5.2 Column Design Criteria / 134
5.3 Rectangular Columns / 135
5.4 Round Columns / 140
5.5 Tapered Columns / 140
5.6 Spaced Columns / 141
5.7 Built-Up Columns / 144
5.8 Columns with Flanges / 146
5.9 Tension Members / 147
5.10 Conclusion / 148
6 TIMBERBEAM-COLUMNSANDTENSIONBEAMS 149
6.1 Introduction / 149
6.2 General Equation for Beam-Columns / 150
CONTENTS vii
6.3 Centric Axial Compression and Side Load Bending about
Both Axes / 156
6.4 Centric Axial Compression and Side Load Bending about
Strong Axis Only / 161
6.5 Eccentric Axial Compression Only / 165
6.6 Axial Compression Eccentricity in Strong Direction
Only / 165
6.7 Columns with Side Brackets / 169
6.8 Combined Axial Tension and Bending / 170
6.9 Conclusion / 173
7 TAPEREDBEAMS 174
7.1 Introduction / 174
7.2 Tapered Beam Design / 176
7.3 Beams with Tapered End Cuts / 183
7.4 Conclusion / 188
8 CURVEDGLULAMBEAMS 189
8.1 Introduction / 189
8.2 Curved Beams with Constant Depth / 195
8.3 Pitched and Tapered Curved Beams / 200
8.4 Pitched and Tapered Curved Beams with Mechanically
Attached Haunch / 223
8.5 Conclusion / 232
9 GLULAMARCHES 233
9.1 Introduction / 233
9.2 Preliminary Design Procedure / 233
9.3 Conclusion / 249
10 HEAVYTIMBERDECKING 251
10.1 Introduction / 251
10.2 Installation Requirements / 251
10.3 Design Formulas / 255
10.4 Section Properties / 256
10.5 Decking Design Values / 257
10.6 Conclusion / 259
viii CONTENTS
11 CONNECTIONSINTIMBERSTRUCTURES 260
11.1 Introduction / 260
11.2 Connection Detailing Principles / 260
11.3 Types of Fasteners / 264
11.4 Reference Design Values for Fasteners / 272
11.5 Adjustment Factors / 274
11.6 Conclusion / 283
12 MEMBERCAPACITYATCONNECTIONS 284
12.1 Introduction / 284
12.2 Member Capacity at Connections Loaded
Perpendicular-to-Grain / 284
12.3 Member Capacity at Connections Loaded
Parallel-to-Grain / 291
12.4 Member Capacity at Connections Loaded at an Angle to
Grain / 307
12.5 Conclusion / 308
13 DOWEL-TYPEFASTENERS 309
13.1 Introduction / 309
13.2 Dowel-Type Fasteners Loaded Laterally / 309
13.3 Dowel-Type Fasteners Loaded in Withdrawal / 328
13.4 Dowel-Type Fasteners Loaded Laterally and in
Withdrawal / 330
13.5 Conclusion / 334
14 SHEARPLATESANDSPLITRINGS 335
14.1 Introduction / 335
14.2 Connectors in Side Grain / 336
14.3 Timber Connectors in End Grain / 347
14.4 Conclusion / 352
15 MOMENTSPLICES 353
15.1 Introduction / 353
15.2 Shear Transfer / 355
15.3 Moment Transfer / 355
15.4 Conclusion / 370
CONTENTS ix
16 LOADANDRESISTANCEFACTORDESIGN 371
16.1 Introduction / 371
16.2 Design Values and Adjustment Factors / 372
16.3 Design Checks / 374
16.4 Conclusion / 381
17 TIMBERBRIDGES 382
17.1 Introduction / 382
17.2 Types of Timber Bridges / 383
17.3 Advantages of Glued Laminated Timber / 389
17.4 Preservative Treatments / 390
17.5 Wearing Surfaces / 391
17.6 Guardrails / 392
17.7 Design Methods / 393
17.8 Conclusion / 395
18 LRFDBRIDGEDESIGN 396
18.1 Introduction / 396
18.2 Longitudinal Stringers / 399
18.3 Transverse Glulam Deck Panels / 418
18.4 Longitudinal Deck (with Stiffeners) / 425
18.5 Conclusion / 432
19 ASDBRIDGEDESIGN 433
19.1 Introduction / 433
19.2 Longitudinal Stringers (Girders) / 436
19.3 Interconnected Transverse Deck Panels / 447
19.4 Non-Interconnected Transverse Deck Panels / 447
19.5 Longitudinal Deck (with Stiffeners) / 457
19.6 Static Design of Guardrail System / 463
19.7 Conclusion / 474
20 FIRESAFETY 475
20.1 Introduction / 475
20.2 Types of Construction / 476
20.3 Lessons from Actual Fires / 476
x CONTENTS
20.4 Performance of Wood in Fire / 478
20.5 Wood versus Steel / 479
20.6 Heavy Timber Construction / 482
20.7 Fire-Resistance-Rated Construction / 483
20.8 Use of Stock Glulam Beams in Fire Rated Construction / 494
20.9 Fire Retardant Treatment / 495
20.10 Conclusion / 495
APPENDIXA DESIGNEXAMPLES 497
Introduction / 498
APPENDIXB REFERENCEINFORMATION 594
B.1 Beam Diagrams and Formulas / 595
B.2 Typical Fastener Dimensions and Yield Strengths / 617
B.3 Structural Glued Laminated Timber Reference Design
Values / 623
REFERENCES 630
INDEX 641
PREFACE
TheAmericanInstituteofTimberConstruction(AITC)hasdevelopedthisTimber
Construction Manual for convenient reference by architects, engineers, contrac-
tors, teachers, the laminating and fabricating industry, and all others having a
need for reliable, up-to-date technical data and recommendations on engineered
timber construction. The information and the recommendations herein are based
on the most reliable technical data available and reflect the commercial prac-
tices found to be most practical. Their application results in structurally sound
construction.
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.
These systems are used in homes; schools; churches; commercial and industrial
buildings; and for other structures such as bridges, towers, and marine installa-
tions. 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 improve-
ments in the structural timber fabricating industry necessitated revisions of the
Manual. New lumber sizes and revisions in grading requirements for lumber
and glued laminated timber were reflected in the second edition published in
1974. The third edition was published in 1985 to reflect new information on
timber design methods. The fourth edition of the Manual was published in 1994
and contained updated design procedures used for timber construction. The fifth
edition (2005) added sections on timber rivet fasteners and load and resistance
factor design.
xi