Introduction to Wood Design: A Learning Guide to Complement the Wood Design Manual

416 Pages·2011·9.113 MB·English

by  Canadian Wood Council

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Introduction
to Wood
Design
2011 Edition
A learning guide
to complement
the Wood Design Manual
Canadian
Wood
Council
Conseil
LIBRARY canadien
B.C. INSTITUTE OF TECHNOLOGY du bois
3700 WILLINGDON AVENUE
BURNABY, B.C.
VSG 3H2
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Introduction to Wood Design
Table of Contents
Introduction
1.1 General Information ............................................................................................................... 1-3
Safety, Reliability and Serviceability
2.1 General Information ............................................................................................................... 2-3
2.2 Design Methods .................................................................................................................... 2-5
2.3 Ultimate and Serviceability Limit States ................................................................................ 2-9
2.4 Structural Reliability ............................................................................................................ 2-11
2.5 Reliability of Wood and Engineered-Wood Products ......................................................... 2-19
2.6 Tables .................................................................................................................................. 2-21
Loads
3.1 General Information .............................................................................................................. 3-3
3.2 Structural Loads .................................................................................................................... 3-5
,---- 3.3 Tables .................................................................................................................................. 3-23
Structural Form
4.1 General Information ............................................................................................................... 4-3
4.2 Factors Influencing Structural Form ...................................................................................... 4-5
4.3 Wood-Frame Construction ................................................................................................. 4-17
4.4 Post and Beam Construction .............................................................................................. 4-21
4.5 Special Structural Forms ..................................................................................................... 4-25
4.6 Lateral Resistance ............................................................................................................... 4-29
4.7 Tables .................................................................................................................................. 4-31
Design Properties of Wood
5.1 General Information ............................................................................................................... 5-3
5.2 Basic Properties .................................................................................................................... 5-5
5.3 Modification Factors ........................................................................................................... 5-21
5.4 Tables .................................................................................................................................. 5-25
Wood Products
6.1 General Information ............................................................................................................... 6-3
6.2 Main Structural Members ...................................................................................................... 6-5
6.3 Sheathing and Decking ....................................................................................................... 6-29
6.4 Tables .................................................................................................................................. 6-37
Bending Members
7.1 General Information ............................................................................................................... 7-3
7.2 Sawn Lumber Bending Members ......................................................................................... 7-5
7.3 Glulam Bending Members .................................................................................................. 7-21
7.4 Tables .................................................................................................................................. 7-33
Compression Members
8.1 Compression Members ......................................................................................................... 8-3
8.2 Tables .................................................................................................................................. 8-11
iv Introduction to Wood Design
Tension Members
9.1 Tension Members .................................................................................................................. 9-3
Combined Axial Loads and Bending Members
10.1 Combined Compression and Bending Members ................................................................ 10-3
10.2 Combined Tension and Bending Members ...................................................................... 10-11
Connections
11.1 General Information ............................................................................................................. 11-3
11.2 General Requirements ........................................................................................................ 11-5
11.3 Split Ring and Shear Plate Connectors ............................................................................. 11-11
11 .4 Bolts and Dowels .............................................................................................................. 11-27
1
11.5 Drift Pins ............................................................................................................................ 11-37
11 .6 Lag Screws ....................................................................................................................... 11-43
11.7 Timber Rivets .................................................................................................................... 11-47
11.8 Truss Plates ....................................................................................................................... 11-53
11 .9 Nails and Spikes ................................................................................................................ 11-55
11 .10 Joist Hangers .................................................................................................................... 11-65
11 .11 Wood Screws .................................................................................................................... 11-67
11.12 Tables ................................................................................................................................ 11-71
Lateral Load Resisting Systems
12.1 General lnformation ............................................................................................................. 12-3
12.2 Shearwall and Diaphragm Action ........................................................................................ 12-5
12.3 Analysis Considerations ...................................................................................................... 12-7
12.4 Construction ...................................................................................................................... 12-11
12.5 Design Procedures ............................................................................................................ 12-15
12.6 Examples ........................................................................................................................... 12-27
12.7 Seismic Design Considerations for Shearwalls and Diaphragms ..................................... 12-37
Sample Building
13.1 General Description ............................................................................................................. 13-3
13.2 Glulam Roof Beam - Simply Supported at Columns ........................................................ 13-13
13.3 Glulam Roof Beam - Cantilever and Suspended .............................................................. 13-15
13.4 Tongue and Groove Decking in Garden Centre ................................................................ 13-21
13.5 Sawn Timber Roof Purlin in Garden Centre ...................................................................... 13-23
13.6 Glulam Header Beam in Garden Centre ........................................................................... 13-25
13. 7 Glulam Roof Header Beam in Office ................................................................................. 13-27
13.8 Wood I-Joist in Office ....................................................................................................... 13-31
13.9 Interior Glulam Column in Showroom ............................................................................... 13-33
13.1O Exterior Bearing Stud Wall in Warehouse ......................................................................... 13-35
13.11 Bolted Connection of Header to Exterior Column ............................................................ 13-37
13.12 Shear Plate Beam-to-Column Connection in Office ......................................................... 13-39
13.13 Timber Rivet Hanger Connection ...................................................................................... 13-43
13.14 Lateral Loads: East-West Direction ................................................................................... 13-47
13.15 Lateral Loads: North-South Direction ............................................................................... 13-55
13.16 Roof Diaphragm and Chords ............................................................................................ 13-59 ---._
13.17 Shearwall, Chords and Tie-Down Connections ................................................................ 13-61
Appendix
A.1 lndex ...................................................................................................................................... A-3
Introduction to Wood Design
Introduction
1.1 General lnformation ............................................ 1-3
\
1-2 Introduction
Introduction to Wood Design 1-3
1.1 General Information
PURPOSE CWC maintains products for facilitating
design and construction, including:
Introduction to Wood Design has been
• Wood Design Manual
prepared to facilitate and encourage the
instruction of wood engineering at Canadian • WoodWorks® Design Software
universities and colleges. The information
• Permanent Wood Foundations
has been prepared in consultation with
• The Span Book
professors to ensure its relevance to the
way wood engineering is taught. • Engineering Guide for Wood Frame
Construction
These notes focus on the engineering
aspects of wood design, which are of primary CWC also publishes a variety of technical
concern to students of engineering. The bulletins, workbooks and fact sheets that
information is also of value to architecture include examples of wood buildings, design
students for developing an understanding details and comparisons between wood and
of structural design principles. other framing materials. These smaller
publications can be downloaded free from
Courses are most often custom tailored by
CWC's web site at www.cwc.ca. The web
each professor. The course content at each
site also contains design tools and general
university or college will vary depending on
information for students and designers
the lecture time available and the personal
wanting to learn more about wood and
style and preferences of each professor.
wood design.
These course notes are meant to cover a
wide range of subjects. For some courses, Every effort has been made to ensure
all the material may be relevant. For other that the data and information in
courses, the professor is of course at liberty Introduction to Wood Design are
to select those subject areas which best suit accurate and complete. The ewe
the time available and the level of familiarity does not, however, assume any
of the students. responsibility for errors or omissions
in the book nor from any designs or
Introduction to Wood Design is intended to
plans prepared from it.
be continually upgraded to meet changing
needs. If students or professors have ewe provides technical assistance to
suggestions for additions, corrections ~designers. If you require information about
or additional design examples, please products, design, or publications, you may
contact the Canadian Wood Council. contact ewe as follows:
Email: [email protected]
CANADIAN WOOD COUNCIL
Web Site: www.cwc.ca
The Canadian Wood Council (CWC) is Errata available at:
privately funded by the manufacturers www.tools.cwc.ca/books
of Canadian wood and engineered wood
products. CWC prepares and distributes
technical information to facilitate the
use of wood products, and is active in
the development and improvement of
building codes and standards throughout
North America.
____
_/
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1-4 Introduction
Introduction to Wood Design 1-5
REFERENCE MATERIALS WoodWorks® is a family of software design
programs. WoodWorks® Sizer offers a
Introduction to Wood Design is intended to conceptual design mode for initial sizing
be used in conjunction with the Wood Design and options analysis. It also offers detailed
Manual 2010. This manual includes CSA design capability for beams and columns
086-09 Engineering Design in Wood. It also including the generation of shear and moment
includes information and selection tables diagrams. WoodWorks® Connections provides
which simplify the design process for the detailed designs for wood beam and wood
examples used in this textbook. The manual column connections. WoodWorks® Shearwalls
is also the reference wood design document is the module that designs shearwalls and
which is used by practising Canadian connections for lateral wind and seismic loads.
engineers.
It is suggested that once students are accus
The National Building Code of Canada tomed to using the member selection tables
(NBCC) is the model building code in Canada in the Wood Design Manual, they become
that forms the basis of most building design acquainted with WoodWorks® programs to
in the country. In terms of structural design, check designs and investigate alternative
the NBCC specifies loads, while material solutions.
resistance is referenced through using the
material Standards. In the case of wood, CSA In this way, students will learn the basics,
Standard 086 provides the designer with the while also learning methods for facilitating
means of calculating the resistance values the design procedures they will apply during
their careers.
of wood. Additional information on loads is
found in the companion document to the
WoodWorks® programs are available to
NBCC - NBC 2010 Structural Commentaries
schools. For more information, contact
(Part 4).
the Canadian Wood Council.
In the design examples, references will be
noted as follows: SAMPLE BUILDING
WDM - Wood Design Manual 2010
The design examples in Chapter 13 of this
CSA 086 - CSA 086-09 Engineering Design publication are based on a sample building.
in Wood In this Chapter, the assignment of loads
and the design of members and connections
NBCC - National Building Code
are interdependent, thus allowing students
of Canada
to develop an understanding of the design
NBCC-SC - User's Guide - NBC 2010 process for all structural aspects of a
Structural Commentaries (Part 4) building design.
The Canadian Wood Council wishes to
WOOD AS AN
assist students to become familiar with
wood design by having them attain an ENGINEERING MATERIAL
understanding of the basic properties
Wood has a long history in Canada as a
of wood, and learning design from first
principles. ewe also recognizes that wood building material.
design is made easier with design aids. Once
students have learned the basics, the Wood
Design Manual offers many shortcuts for
member selection.
1-6 Introduction