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Wood Design Manual 2005

Wood Design Manual

2005

The complete reference for wood design in Canada

Canadian Wood Council Conseil canadien du bois

© 2005 Copyright Canadian Wood Council Conseil canadien du bois Ottawa, Ontario, Canada www.cwc.ca ISBN 0-921628-75-7 (ISBN 0-921628-62-5. 4th revised edition, 2001 ISBN 0-921628-50-1. 3rd revised edition, 1997 ISBN 0-921628-33-1 . 2nd revised edition, 1995 ISBN 0-921628-04-8. 1st edition , 1990)

2.0M05-12, 2.0M06-11, 2.0M08-01

Illustrations: RJS 10 Inc., Ottawa, ON

Book design and production: Eton Systems, Nepean, ON

Printing: Friesens, Altona, MB

With the permission of Canadian Standards Association, material is reproduced from CSA Standard CAN/CSA-08601, Engineering Design in Wood, which is copyrighted by Canadian Standards Association, 5060 Spectrum Way, Suite 100, Mississauga, ON, Canada, L4W 5N6. While use of this material has been authorized, CSA shall not be responsible for the manner in which the information is presented nor for any interpretations thereof.

*

Printed in Canada on recycled paper.

Wood Design Manual

Preface The Canadian Wood Council (CWC) is the association responsible for the development and dissemination of technical information on the use of wood products in construction. Ensuring that this information is in tune with technical change and users' needs requires constant vigilance. The purpose of this fifth edition of the Wood Design Manual is to help the Canadian design community - architects, engineers, specification writers, teachers and students of these disciplines - to design wood structures with efficiency, economy and safety. It brings together, in a comprehensive but concise format, the essential information a designer needs for a wide range of wood structural elements and systems. The information in the Wood Design Manual is based on the latest information available from the National Building Code of Canada (2005) and from CSA Standard 086-01 (2005) Engineering Design in Wood. Every effort has been made to ensure that the data and information in the Manual are accurate and complete. The CWC does not, however, assume any responsibility for errors or omissions in the Manual nor for engineering designs or plans prepared from it. The CWC would like to thank the individuals who were instrumental in the development of this manual: Stephen J. Boyd, Quaile Engineering Ltd ., and Gary C. Williams, President, Timber Systems Limited. Pauline Rochefort President November 2005

' For information on ewe's other design tools, call this toll-free number: 1-800-463-509 1 or visit the ewe web site at www.cwc.ca

ii

Wood Design Manual

iii

Sustainable Building Materials Wood is the Natural Choice Sustainable Buildings and Green Buildings are gaining interest of designers looking to conserve energy and minimize the environmental impact of buildings using four generally accepted objectives to reduce the global impact of a particular product or system: • Reduced energy and resource use in extraction and processing • Reduced energy consumption in processing and end use • Minimized external pollution and environmental damage throughout the life cycle • Minimized internal pollution in the built environment. Wood is the best environmental choice to meet these four principles based on the following: • Wood is the only renewable major construction material • Wood is energy efficient in manufacture and use • Wood is easily recycled or re-used • Wood minimizes environmental impact • Canadian wood products are produced from well managed forests that are regulated by sustainable forestry policy. Life-Cycle Assessment

Life Cycle Assessment is a performance-based approach to assessing the impacts that building products or systems have on the environment over their lifetime. This includes all activities from material extraction or harvesting through manufacturing, transportation, installation, use, maintenance, and final disposal or re-use. LCA is the best available tool to compare sustainability of building materials. When considering environmental impact using Life Cycle Assessment, wood outperforms other major building materials in the following ways: • Requires less embodied energy in production • Reduces greenhouse gas emissions • Releases fewer pollutants into the air • Discharges less water pollutants • Generates fewer solid wastes.

iv

Environmental Benefits of Building with Wood

Sustainable Forest Management

Canada is a world leader in forest conservation, protection and sustainable use. 94% of Canada's forests are on crown land and provincial governments enforce strict guidelines on harvesting, regenerating and sustaining these publicly owned forests. For example: • Canada has the largest area of legally protected forests in the world • Canada has the largest area of original forest cover in the world (over 90%) • Only one-quarter of Canada's forests are managed for commercial use • Annually, Canada harvests less than one-half of 1% of its forest • Canada has the largest area of independently certified forests in the world Canada's history of caring for our resource base and our desire to continually improve has made these facts a reality. Canadian law, as it now stands, has some of the most progressive legislation for forest management in the world. Public concerns focus on the highly visible effects of wood resource extraction. To address these concerns, Canadian wood product manufacturers are using certification by qualified, 3 rd party, independent bodies to attest that they meet the requirements of a rigorous and independent forest management standard. Canadian companies have achieved third-party certification on over 100 million hectares (250 million acres) of forests, the largest area of certified forests in the world.

v

Wood Design Manual

Table of Contents Introduction

1.1 1.2

General Information .................. 3 Limit States Design .... .... .. ... ..... 5

Bending Members

2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8

General Information ... . . .. .. . . . . . ... 15 Sheathing & Decking .. . . . . . . ... ... .. 17 Lumber Joists ............ . .... . .. . . 31 Engineered Joists ... . . . ............. 45 Beams and Purlins ...... . .... . ... . . . 49 Built-up Beams .. .. .. . . ... .. ... . . . . . 73 Two-way Bending Members .. . . . . ... . . 75 Cantilevered Beams ....... . .. . .. . ... 83

Compression Members

3.1 3.2 3.3 3.4

General Information ........ . ........ 95 Stud Walls and Posts . . . . . . . . . . . ..... 97 Columns .... . ......... . ........ . . 111 Built-up Columns .... .......... .... 141

3

II Tension Members

4.1 4.2

General Information .. . . ............ 153 Lumber and Glulam ..... . ...... . ... 155

Combined Loads

5.1 5.2

General Information . . . ... . . . . ...... 175 Stud Walls .......... . ... . . . .. . . .. 191

5

vi

Table of Contents

Bearing

6.1 6.2 6.3

General Information ................ 211 Bearing Resistance of Wood ......... 213 Bearing Plates .............. .. .... 219

Fastenings

7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9 7.10 7.11

General Information .... . . . .... .. ... 231 Nails and Spikes .................. 237 Bolts . . . . . . . ... .... . . .. .......... 245 Drift Pins ................ . . ... ... 267 Lag Screws .. . ................... 269 Timber Rivets . .... . ... . .. ... ... . .. 281 Shear Plates and Split Rings ..... ... . 301 Truss Plates ... . .... . . . . .. ... ..... 321 Joist Hangers ............. . . ...... 329 Framing Anchors .. . .... .. ....... .. 331 Typical Connection Details . . . . . . .... 335

Applications

8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9 8.10

General Information . ............... 371 Curved Glulam . . .... . . .. .. . .. . . . .. 373 Timber Arches . . ... .. . . . . . .. ... . .. 379 Pitched-tapered Beams . . ........... 389 Pyramidal, Domed and A-frame Buildings . 403 Heavy Timber Trusses ........... . .. 407 Light Frame Trusses .. ...... ....... 413 Permanent Wood Foundations .. . .... 423 Stressed-skin Panels ........ ...... . 431 Concrete Formwork ........... .... . 435

Shearwalls and Diaphragms

9.1 9.2 9.3

General Information .... ... ......... 451 Diaphragm Design ....... . . . . .. ... . 455 Shearwall Design ........... . .. .. . 469

Design for Fire Safety

10.1 10.2 10.3 10.4 10.5 10.6 10.7

General Information ...... .. . ....... 495 Definitions .. . . . . .... . .. . . . . ... . .. 497 Wood Construction ................ 499 Fire-resistance Rating .... . ... . ..... 503 Determining Fire-resistance Ratings . .... 507" Flame-spread Ratings ............. . 515 Fire-retardant Treated Wood ......... 517

7

I-a ~

9

10

vii

Wood Desig n Manual

Reference Information

11 .1 General Information ......• . . . . . . . .. 523 11 .2 Section Index .. .... . .... .. .. . . . . . . 523

CSA commentary

12.1 Reliability-based Design ...... . ..... 593 12.2 Load Duration . .. ...... . .. . . ...... 599 12.3 System Modification Factors and Floor Vibration . ............... 603 12.4 Sawn Lumber . . . . . ... ... •.... .... 607 12.5 Glulam . . . . . . . .... . .. .. ... . .. .. . . 625 12.6 Structural Panels ......... . .. ... . .. 637 12.7 Composite Building Components ...... 651 12.8 Shearwalis and Diaphragms ....... . . 657 12.9 Fastenings ... .... . . . ... . ... . ..... 671 12.10 Proprietary Structural Wood Products ... 693

CSA 086

Reprint of CSA 086 ... . . . .... ..... gray pages

Appendix

List of Symbols ... ..... . ....... . ...... .. A-3 Index ............. ... . .. ...... ... ..... A-7

11

12

viii

Introduction

1.1 General Information . . . . . .. .... . . . .. .... 3 1.2 Limit States Design .................... 5

1

2

Introduction

Wood Design Manual

1.1

3

General Information The design information provided in this manual is based on the Canadian Standards Association (CSA) Standard CSA 086 Engineering Design in Wood (Limit States Design).

1

Member Design [

The chapters that deal with the design of members provide selection tables listing factored resistances and stiffnesses for common sizes. The tabulated values have been calculated from CSA 086 using modification factors for conditions most often encountered in the design of wood structures. The designer must verify that the tabulated values are appropriate for a particular structure being designed by reviewing the checklist provided before each set of tables. In most chapters, modification factors are provided so that the tabulated values may be adjusted for different conditions. Where a direct modification of the tabulated value is not possible, a simplified design equation is provided to calculate the resistance; however, the tables may be used to select a trial section . Chapters are arranged so that the lightest load-carrying element is presented first and the heaviest last. For example , Chapter 2 Bending Members begins with sheathing and decking followed by joists and beams. This arrangement should assist the designer in making economical choices for an efficient deSign. Fastenings Design

The design approach for fastenings is somewhat different since the resistance of a particular fastener often depends on a larger number of variables. For each fastener, a simplified formula for factored resistance is provided. The formula generally includes a number of modification factors which may be determined using a checklist. The checklist indicates the conditions where each factor is equal to unity, and where it is not. This enables the designer to quickly adjust the nominal resistance for the actual conditions and also ensures that all of the factors have been considered. Where applicable, diagrams are provided showing edge distance, end distance and spacings for different sizes of fasteners in order to assist the designer in detailing the connections. Reference Material

Chapter 11 Reference Information provides background material on a variety of topics. Of particular importance to the design of members and fasteners is the description of duration of load and service conditions. In addition, information on species combinations, grades and sizes of lumber is included. Chapter 11 also contains beam diagrams and formulae, deflection factors and standard dimensions of fastening hardware.

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4

Introduction

Wood Desig n Manual

1.2

5

Limit States Design General

1

The limit states design approach is to provide adequate resistance to certain limit states, namely strength and serviceability. Strength limit states refer to the maximum load-carrying capacity of the structure. Serviceability limit states are those that restrict the normal use and occupancy of the structure such as excessive deflection or vibration. The National Building Code of Canada (NBCC) applies factors of safety to both the resistance side and the load side of the design equation. The design criterion to be satisfied then becomes the following: Factored resistance

~

factored load effect

The factored resistance is the product of a resistance factor and the nominal resistance , both of which are given in CSA 086 for wood materials and fasteners. The resistance factor takes into account the variability of dimensions and material properties, workmanship, type of failure , and uncertainty in the prediction of resistance . The factored load effect is calculated in accordance with the NBCC by multiplying the actual loads on the structure (specified loads) by load factors that account for the variability of the load. A summary of the NBCC loading is given below.

Specified Loads and Combinations Revisions have been made to the limit states requirements in the 2005 edition of the NBCC: These include : Adoption of the companion action format for load combinations. Separation of load due to snow and rain from live load due to use and occupancy. Use of importance factors to determine the specified snow and rain , wind and earthquake loads. The importance factors are dependant on the type of load and the building use and occupancy. Separate importance factors are used to determine serviceability loads. Modification of the return period for snow, rain and wind loads from 1/30 to 1/50 probability of exceedence per year.

6

Introduction

Specified Loads Loads to be considered are: D - dead load due to the weight of building components E - load due to earthquake, including the effect of the importance factors L - live load due to use and occupancy S - load due to snow and rain, including the effect of the importance factors W - load due to wind, including the effect of the importance factors H - load due to lateral earth pressure P - permanent effects caused by prestress T - load due to temperature, shrinkage and settlement effects Specified earthquake load, E; snow load, S; and wind load, W incorporate the importance factors shown in Table 1.1. Table 1.1

Importance factors for determining S, W, and E loads

Importance factors for snow loads, Is

Importance factors for wind loads, Iw

Importance factors for earthquake loads, IE

Importance category

Ultimate limit state

Serviceability limit state

Ultimate limit state

Serviceability limit state

Ultimate limit state

Serviceability limit state

Low

0.8

0.9

0.8

0.75

0.8

N/A

Normal

1.0

0.9

1.0

0.75

1.0

N/A

High

1.15

0.9

1.15

0.75

1.3

N/A

Post-disaster

1.25

0.9

1.25

0.75

1.5

N/A

Importance categories for buildings are based on intended use and occupancy as follows: Low - Buildings that represent a low hazard to human life in the event of failure Normal - All buildings except those listed as low, high or post-disaster High - Buildings that are likely to be used as post-disaster shelters, including schools and community centres Post-disaster - Buildings that are essential to provide services in the event of a disaster Load Combinations for Ultimate Limit States The effect of principal plus companion loads is determined using the load combinations in the building code as shown in Table 1.2. The load effect should be in the same units as the resistance (i.e., kN, kN-m) and should be the most unfavourable effect considering all possible load combinations.

I

j

Wood Design Manual

Table 1.2 Load combinations for ultimate limit states

7

Case

Principal loads

Companion loads

1 2 3 4 5

1.40 (1.250 (1.250 (1.250 1.00 +

0.5S or O.4W 0.5L3 or O.4W 0.5L3 or 0.5S 0.5L3 + 0.25S

or 0.90) + 1.5L2 or 0.90) + 1.5S or 0.90) + 1.4W 1.0E

Notes: 1. Refer to the NBCC for ; • dead load, 0 , for soil , • guidance on combining snow load, S, and live load, L, on exterior areas, • loads due to lateral earth pressure, H, prestress, P, and imposed deformation , T. 2. The principal load factor of 1.5 for a live load, L, may be reduced to 1.25 for liquids in tanks. 3. The companion load factor of 0.5 for a live load, L, shall be increased to 1.0 for storage occupancies, equipment areas and service rooms .

Load Combinations for Serviceability Limit States The effect of principal plus companion loads is determined using the load combinations specified in CSA 086 as shown in Table 1.3. Table 1.3 Load combinations for serviceability limit states

Case

Principal loads

Companion loads

1 2 3

1.00 1.00 + 1.0L 1.00+1 .0S 1.00 + 1.0W

0.5S or O.4W 0.5L or O.4W 0.5L or 0.5S

4

Notes: 1. Oead loads include permanent loads due to lateral earth pressure, H, and prestress, P. 2. Refer to the NBCC for guidance on combining snow load, S, and live load, L, on exterior areas.

Example: Lintel Loads Determine the design loads for the following conditions lintel supporting roof and one floor of a school lintel span = 3 m

=3 m tributary width of floor =3 m specified roof dead load = 1 kPa

tributary width of roof

specified floor dead load = 1.5 kPa

1 in 50 year ground snow load, Ss = 1.8 kPa 1 in 50 year associated rain load, Sr = 0.2 kPa basic snow load factor, Cb =0.8; snow load wind exposure factor, Cw =1.0; snow load slope factor, Cs = 1.0; snow load shape factor, Ca = 1.0 specified floor live load

=2.4 kPa

1

8

Introduction

Calculation Ultimate limit states: Uniform specified dead load w D = (1 x 3) + (1.5 x 3) = 7.5 kN/m Uniform specified live load wL = (3 x 2.4) = 7.2 kN/m Specified snow load S = Is[Ss(CbCwCsCa) + Sr] = 1.15[1.8(0.8 x 1.0 x 1.0 x 1.0) + 0.2] = 1.89 kPa Uniform specified snow load Ws

=3 x 1.89 =5.67 kN/m

0:

WI = 1.4 x 7.5 = 10.5 kN/m D+S+L:

= (1.25 x 7.5) + (1.5 x 7.2) + (0.5 x 5.67) = 23.01 kN/m = (1.25 x 7.5) + (1.5 x 5.67) + (0.5 x 7.2) = 21.48 kN/m

WI WI

Governs O+S+L

Serviceability limit state: Specified snow load S

= Is[Ss(CbCwCsCa) + Sr] =0.9[1.8(0.8 x 1.0 x 1.0 x

1.0) + 0.2]

= 1.48 kPa

Uniform specified snow load Ws

= 3 x 1.48 = 4.43 kN/m

0:

w

= 7.5 kN/m

D+S+L: w

=7.5 + 7.2 + (0.5 x 4.43) = 16.92 kN/m

w

= 7.5 + 4.43 + (0.5 x 7.2) = 15.53 kN/m

Governs O+S+L

S+L: W =7.2 + (0.5 x 4.43)

=9.41

kN/m

Governs S+L

W = 4.43 + (0.5 x 7.2) = 8.03 kN/m

Use the following loads for design: Ultimate limit states -10.5 kNlm, D; and 23.0 kNlm, D+S+L Serviceability limit states -7.5 kNlm, D; 16.9 kNlm, D+S+L; and 9.4 kNlm, S+L

'

Bending Members

2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8

General Information .. . . . . . ...... . ... . . 15 Sheathing & Decking ... .... . ..... .. . . . 17 Lumber Joists .. .. .... . . . ... . ... . . . .. 31 Engineered Joists . .. . .... .. ..... ..... 45 Beams and Purlins .. . .. . ... . . . .... . .. 49 Built-up Beams . . . . .. ......... . ...... 73 Two-way Bending Members . .. . . .. . . ... 75 Cantilevered Beams ....... .. .. . . . .... 83

2

10

Bending Members

Wood Design Manual

The sweeping form of these 50 m span arches provides a dramatic structure for this skating arena. The frame. purlins and decking satisfy the NBCC "Heavy Timber Construction" requirements for fire safety.

11

12

Top left: Tongue and groove decking is manufactured from several species, and usually has a vee joint on the exposed face. Top right: Double tongue and groove 64 mm and 89 mm thick decking is predrilled at 760 mm on centre for side nailing with 200 mm spikes. Middle left: Structural Composite lumber (SCl) and glulam beams provide significantly higher design values than sawn lumber. Middle right: Wood I-joists are stocked in long lengths and a range of depths for use as secondary framing members. Bottom: Non-residential applications may be framed very competitively with glulam beams and a number of sheathing materials, including steel decking.

Bending Members

Wood Design Manual

Glulam beams and wood I-joists are readily integrated with steel columns in this structure.

Joists in the typical floor layout shown here are usually provided in No.1 or No.2 grade, both of which have the same specified strengths.

13

14

Glulam beams are commonly used as primary framing members and can be left exposed to form an architectural feature .

Bending Members

15

Wood Design Manual

2.1

General Information The following sections contain design information for members that are used in bending or flexure. These members include sheathing and decking, joists, beams and purlins. Additional design information is included for built-up beams, oblique purlins and cantilevered beams. While the tables in this chapter deal only with bending moment, shear resistance and stiffness, the designer must also be concerned with bearing of the bending members on their supports. Chapter 6 provides design information for bearing and compression loads perpendicular to the grain . The Sheathing Selection Tables provide the recommended thicknesses of waferboard, oriented strandboard and plywood for use on floors and roofs for various joist spacings. These thicknesses are recommended by Part 9 of the National Building Code of Canada (NBCC), the Canadian Plywood Association (Can Ply) and the Structural Board Association (SBA) . Selection tables for joists, beams and purlins are arranged to provide moment and shear resistances, and bending stiffnesses (Esl) for given species, grades and size combinations. The design tables presented in this chapter are based upon conditions that are typical for most building structures. Checklists are also given before each set of tables.The designer should review these checklists to be sure that the tabulated resistance is appropriate for the actual conditions of use. Serviceability

Adequate bending stiffness should be provided so that the maximum deflection (~max) of the member does not exceed the values given in Table 2.1. A serviceability table is provided in Section 2.3 to assist in determining the required bending stiffness for a deflection criterion of U360. For conditions outside the scope of the serviceability table, the designer should calculate a required Esl and compare it with the tabulated Esl values. The tabulated Esl values are based on bending about the strong axis (depth) except as noted. Table 2.1 Deflection Criteria

Loading Roofs and floors Plastered or gypsum ceilings:

Total load Glulam

Live load

Lumber

Total load

Roofs

Live load

Floors

Live load 3

Wind columns

Wind load

"'max

U180 U360 U360' U240 2 U360 U180

Limitation CSA086 Suggested Suggested Suggested Suggested Suggested

Notes: 1. Part 9 of the NBCC permits U360 deflection limitation based on live load for all roofs and floors with plaster or gypsum board. 2. In Part 9, this is required for roofs with ceilings other than plaster or gypsum . Where no ceilings exist, U180 based on live load is permitted. 3. For floor beams supporting floors with concrete topping , U360 based on total specified load is recommended. 4. For curved glulam members, refer to Section 8.2 and clause 4.5.2 of CSA 086.

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16

Bending Members

The serviceability of structures subject to ponding should be investigated, and guidance is given in CSA 086 Section 4.5.4. Consideration should also be given to structures subject to vibration. Although CSA 086 provides no specific guidelines, the designer may refer to Appendix A-9.23.4.2 of the NBCC. This article of the NBCC contains span tables for jOists in Part 9 buildings which incorporate vibration criteria (see Chapter 11). Additional guidance on floor vibration can be found in the Commentaries to Part 4 of the NBCC and the CSA 086 Commentary.

Wood Design Manual

2.2

17

Sheathing & Decking Structural sheathing is manufactured from a wide variety of wood-based materials. Plywood, oriented strandboard (OS8) and waferboard are the most commonly used panel products for structural roof, wall and floor sheathing. They are generally used on joists or light frame trusses spaced no more than 610 mm apart. Plank decking may be used to span farther and carry greater loads than panel products. Decking is generally used in combination with heavy timber or glulam structures and often where fire performance must meet the heavy timber construction requirements of Part 3 of the National Building Code of Canada.

Plywood Sheathing Plywood panels are built-up from sheets of softwood veneer glued together with a waterproof resin adhesive. Typically the grain direction and thickness about the panel centreline is balanced. Douglas Fir Plywood (DFP) and Canadian Softwood Plywood (CSP) are the two most common softwood plywoods produced conforming respectively to CSA Standard 0121 , Douglas Fir Plywood, and 0151, Canadian Softwood Plywood. Typical sizes of plywood are shown in Table 2.2. Tongue and groove (T&G) plywood is a standard panel with a factorymachined tongue along one of the long edges and a groove along the other. During installation, T&G plywood provides effective load transfer between adjacent panels. These metric panel thicknesses are similar to the imperial sizes, which have been established through experience and traditional usage. The length and width of panels are typically used with supporting members spaced at 305 mm (12"), 406 mm (16"), 488 mm (19.2") or 610 mm (24"). Table 2.2 Typical plywood sizes\ nominal thicknesses 2

Sheathing and selected grades mm

Sanded grades mm

7.5

6.0

9.5

B.O

11.03 12.53

11.0

15.54

14.0

1B.54

17.04

20.54

19.0 4

22.54

21.0 4

25.54

24.0 4

2B.54

27.04

31 .54

30.0 4

Notes : 1. Nominal panel sizes of 1220 x 2440 mm (4' x B') or cut to size. Larger panel sizes may be available on a limited special order basis. 2. All thicknesses are metric. Some, but not all , thicknesses approximate imperial dimensions, namely : 6 mm (114") , 9.5 mm (3/B") , 12.5 mm (1/2"), 15.5 mm (5/B"), 19 mm (3/4"), 22.5 mm (7/B") , 25.5 mm (1"), 2B .5 mm (1-1/B") , and 31.5 mm (1-1/4") . 3. Available as square edge (except 11 .0 mm) or with EASY T&G Roof edge profile. 4. Available as square edge or with EASY T&G Floor edge profile.

2

18

Bending Members

Oriented Strand board (OS8) and Waferboard Oriented strand board (OSB) and waferboard are structural mat-formed panel products made of thin strands or wafers, sliced from small-diameter round wood logs or blocks, and bonded with exterior-type binder under heat and pressure. OSB is manufactured with the surface layer strands aligned in the long panel direction, while the inner layers have random or cross alignment. Waferboard on the other hand has all the wafers randomly aligned throughout the panel. OSB and waferboard panels are manufactured in both imperial and metric sizes, and are either square-edged or tongue-and-grooved on the long edges for panels 15 mm (19/32") or thicker. The sizes shown in Table 2.3 are most common. The general product standard is GSA 0437, and Waferboard. The product standard contains three designations: 0-1 and 0-2 indicate alignment of the strands as in OSB; while R-1 indicates random alignment, and is less common. Another standard that applies to OSB and waferboard, as well as to plywood, is a performance standard: GSA 0325, Construction Sheathing. This standard sets performance ratings (Table 2.4) for specific end uses such as floor, roof and wall sheathing in light-frame construction. It is referenced in Part 9 of the NaCC, and provides an alternative way of specifying products for these applications without referencing product standards. In addition to the Part 9 reference, design values for construction sheathing OSB conforming to GSA 0325 are listed in GSA 086 allowing engineering design of roof sheathing, wall sheathing and floor sheathing using GSA 0325 rated OSB. OSB can be certified specifically for engineered design applications, in accordance with GSA Standard 0452, Design Rated (Table 2.5) . This standard contains certification and grade-marking requirements for three types of design-rated OSB panels:

asa

asa

• Type 1 (STANDARD): products consisting of three different rating grades (A, B or G), with design values listed in GSA 086. • Type 2 (PLUS): products exceeding Type 1 rating grade levels by 10% or more (noted on grade mark). • Type 3 (PROPRIETARY): products for which a certification organization certifies specified design capacities, different from STANDARD or PLUS capacities. Designers should ensure the availability of design-rated OSB before specifying.

Wood Design Manual

Table 2.3 eSA 0437 sizes for ose and waferboard

Imperial thickness (in.)

19

Metric thicknesses for the following grades (mm) 0-2

0-1

R-1

1/4

6.00

6.35

6.35

5/16

7.50

7.90

7.90

3/8

9.50

9.50

9.50

7/16

11 .0

11 .1

11 .1

15/32

12.0

1/2

12.5

12.7

12.7

19/32

15.0

5/8

15.5

23/32

18.0

3/4

18.5

7/8

22.5

1-1/8

28.5

2

!D

ID :::I

Q,

s·

ea

15.9

15.9

s: ell

19.0

iil

3

g 19.0

Note : Panel sizes are 4' x 8' (1220 x 2440 mm) or cut to size. Larger sizes up to 8' x 24' (2440 x 7320 mm) are available on special order. Table 2.4 eSA0325 performance marks

Spacing in inches (mm) 16 (400)

Assumed end use

20 (500)

24 (600)

32 (800) 1F32

40 (1000)

48 (1200)

Subflooring

(1 F)

1F16

1F20

1 F24

Subflooring used with a panel-type underlay

(2F)

2F16

2F20

2F24

Roof sheathing used without edge support

(1R)

1R16

1R20

1R24

1R32

1R40

1R48

Roof sheathing used with edge support

(2R)

2R16

2R20

2R24

2R32

2R40

2R48

Wall sheathing

(W)

W16

W20

W24

3

3

1F48 _ 3

Notes: 1. Panel marks consist of an end use mark followed by the appropriate span mark. 2. Multiple panel marks may be used on panels qualified for more than one end use, e.g., 1R24/2F16 or 2R48/2F24/1 F24. 3. Not covered by this Standard. Table 2.5 eSA0452 design-rated

ose

Product type

Design rating grade

1 (STANDARD) 2 (PLUS)

A B

C 3 (PROPRIETARY)

Nominal thickness (mm) 9.5 to 28.5 unspecified

Note: Structural properties (strength and stiffness) are given for bending, axial (tension and compression) and shear (in-plane and through-the-thickness). Values are listed for forces applied parallel and perpendicular to major axis (or length) of the panel.

7

!

20

Bending Members

Sheathing Selection Tables

The roof and floor Sheathing Selection Tables provide the recommended panel thickness for the most common support spacings. These thicknesses conform to NBCC requirements for Part 9 buildings when applicable, reflecting past experience. The tables have been extended to meet the same criteria. The plywood, aSB and waferboard thickness for floors with live loads of up to 4.8 kPa are recommended by the Canadian Plywood Association and the Structural Board Association, respectively.

, 26

Bending Members

Modification Factors The tabulated maximum uniform loads for plank decking are based upon the following formulae and modification factors. When using the tables, be certain the member conforms exactly to the modification factors used in the tables; if not, use the factors below and make the necessary adjustments to the tabulated values.

W ~R =

34.6x10-9 Es d3 K~ Kspan 3

L

(kPa)

where: w FR == maximum factored load capacity (kPa) w ~R == maximum specified load capacity based on deflection limitations (kPa) Fb == fb (Ko KH KSb KT) (MPa) fb == specified strength in bending (MPa) Fy -3K zy (N) Esl = E (KSE KT) I (N-mm 2) Fr = Ff A KN (N) (for joists with notches on the tension side at supports)

Vr

where:

Fb fb S Fy fv A E

= 0.9 = fb (Ko KH KSb KT ) (MPa) = specified bending strength (MPa) = section modulus (mm 3 ) = fy (Ko KH Ksv KT) (MPa) = specified shear strength (MPa) = gross cross-section area (mm2) = specified modulus of elasticity (MPa) = moment of inertia (mm4)

34

Bending Members

and for joists with notches on the tension side at supports: Ff = ff (Ko KH KSf KT) (MPa) ff = specified notch shear force resistance, 0.5 MPa for all sawn members Ko is a load duration factor. The tabulated resistances are based on a "standard" term load, which includes the effects of dead loads plus live loads due to use and occupancy, and snow loads. (Ko = 1.0). For structures intended to support permanent loads the Mr and Vr values must be multiplied by 0.65. For joists intended to support short term loads such as wind and earthquakes, Mr and Vr may be multiplied by 1.15.

KH

is a system factor. The factor is incorporated in the tables as noted.

Ks is a service condition factor. The tabulated values (and Esl values) are based on dry service (Ks = 1.0). For wet service conditions, multiply the tabulated values by the following factors:

= 0.84 for Mr Ksv = 0.96 for Vr KSb

KSf = 0.70 for Fr KSE = 0.94 for Esl

KT is a treatment factor. The tabulated resistances are based on joists that are either untreated or treated with a non-strength-reducing chemical (KT = 1.0). Most wood preservatives do not reduce strength unless the lumber has been incised. However, most fire retardants will reduce strength. If the material is treated with a fire retardant or if it is incised prior to preservative treatment, multiply the tabulated values by the following factors: Table 2.6 Treatment factor KT

KT for Mr and Vr Treatment type Preservative treated, incised lumber Fire-retardant treated lumber

Kz

Dry

KT for Esl

Dry

service

Wet service

service

Wet service

0.75

0.85

0.90

0.95

refer to Commentary

is a size factor incorporated in the tables for given material dimensions.

KN is a notch factor for notches located on the tension side of the member at a support:

Wood Design Manual

35

where : = depth of joist (mm) d n = depth of notch (mm), must not exceed 0.25d

d a

= 1 - (did)

1']

= e/d

e

= length of notch (mm), from centre of nearest support to reentrant corner of notch. Length of support may be taken as the minimum required bearing length .

2 ID CD

"

a. 5·

Ul

3: CD

3

go

iii

e

e

Note: Where a member is notched, the tabulated shear resistance values, Vr , must be adjusted by An/A where An is the net cross-sectional area at the notch and A is the gross cross-sectional area.

KL is a lateral stability factor. The tables are based on joists that are restrained against lateral displacement and rotation at their ends, the compressive edges are held in line by the sheathing , and bridging is provided at intervals not exceeding 8 times the member depth (K L = 1.0). For depth to width ratios of 6.5:1 or less, the bridging may be omitted. If the joists lack this restraint, refer to CSA 086 (Clauses 5.5.4.2 and 6.5.6.4) for the appropriate adjustment factor.

36

Bending Members

Example 1 : Joists

Design single span floor joists for the following conditions: o o o o o o o o o

joist spacing =400 mm joist span =3.0 m specified dead load = 1.5 kPa (includes partitions) specified live load = 2.4 kPa (commercial use and occupancy) standard load duration dry service condition untreated fully laterally supported by subfloor Case 2 system

Use S-P-F NO.1/No.2 sawn lumber. Calculation

Total factored load = (1.25 x 1.5) + (1.5 x 2.4) = 5.48 kPa Total specified load = 1.5 + 2.4 =3.90 kPa wf = 5.48 x 0.40 = 2.19 kN/m W = 3.90 x 0.40 = 1.56 kN/m wL

= 2.40 x 0.40 = 0.96 kN/m

W L2 Mf = _f_ 8

Vf =

wfL 2

=

2.19 X 3.0 2 8 2.19 x3.0

2

=

=

2.46 kNLm

3.29 kN

Calculate a required Esl for the specified live load or select the required Esl from the Serviceability Table. Esl REQ'D = 122 x 109 N omm 2 for L/360 deflection based on live load (w From Joist Selection Tables select 38 x 184 mm: Mr Vr Esl

= 3,83 > 2.46 kN om = 10.6> 3.29 kN = 187 x 109 > 122 x

Acceptable Acceptable

109

N omm 2

Note: Verify acceptable bearing capacity as per Chapter 6 Use 38 x 184 mm No.1INo.2 S-P-F sawn lumber.

b

Acceptable

L)

Wood Design Manual

37

Example 2: Joists notched on tension side at supports Verify that the Hem-Fir No.1 INo.2 38 x 286 mm floor jOists (see drawing) notched at the supports are adequate for the following conditions : jOist spacing = 600 mm joist span = 4.0 m specified dead load = 1.2 kPa ° specified live load = 2.4 kPa standard load duration ° dry service conditions ° untreated ° fully laterally supported by subfloor Case 2 system °

140 mm -t--- -i ...-_70.!0'.::m~m~::;::;:r-70 mm

°

IJI ~

286mm

:s

Q.

s·

cc

i

3

i

til Centre line - -_ ofsupport

Calculation Total factored load = (1.25 x 1.20) + (1.5 x 2.40) = 5.10 kPa Total specified load = 1.20 + 2.40 = 3.60 kPa

wL

= 5.10 x 0.6 = 3.06 kN/m = 3.60 x 0.6 = 2.16 kN/m = 2.40 x 0.6 = 1.44 kN/m

Mf

=

Vf

= 2f = 9424 mm 2

wf w

.::.1...=....

w L2

3.06 x 4.0 2

8

8

w L

3.06 x 4.0 2

=

6.12kN om 6.12 kN

An A = 10870 mm2 An/A

=0.87

Note: In this example, the maximum factored reaction force Of is equal to Vf' From the Serviceability Table: ESIREQ'D = 432 x 109 N omm 2 for U360 deflection based on live load (w L) From Joist Selection Tables: Mr Vr

= 7.18> 6.12 kNom = 14.6 x 0.87 = 12.70> 6.12 kN

Acceptable

N omm 2

Acceptable

Esl = 815

x 109

> 432

x 109

The factored notch shear force resistance at the support:

Acceptable

38

Bending Members

Ff A

= FfAKN = 0.9 = 0.5 x 1.4 = 0.7 MPa = 38 x 286 = 10868 mm 2

KN

=

[O.006d [16 [~ +~2 [a~ -1]]]"

a

=

1- dn d

11

=

-

Fr

KN

=

e d

=

=

1- 38 286

70 286

-

=

=

0.87

0.24

[0.006 x 286 [1.6

[0.~7 -1] + 0.242 [0.~73 -1] ]]

-05

.

1.45

Note: As an alternative, KN may also be calculated using Table 5.5.5.4 of CSA086. Therefore: Fr

= 0.9 x 0.7 x 10868 x 1.45 = 9.93 kN > Of = 6.12 kN

Acceptable

Note: Also verify acceptable bearing capacity as per Chapter 6.

Wood Design Manual

39

Joist Selection Tables Sawn Lumber Single member

NO.1/No.2

Esl

Size (b x d) Mr kNom mm

Vr kN

Mr kNom

Vr kN

x 10 9 Nomm 2

D.Fir-L

38 38 38 38 38 38

x 89 x 114 x 140 x 184 x 235 x 286

1.27 1.83 2.58 3.82 5.71 7.69

6.55 7.41 8.49 9.57 11 .2 12.4

1.77 2.57 3.61 5.35 8.00 10.8

9.18 10.4 11 .9 13.4 15.7 17.3

27.9 58.6 109 247 514 926

Hem-Fir

38 38 38 38 38 38

x x x x x x

89 114 140 184 235 286

1.23 1.78 2.50 3.71 5.54 7.46

5.52 6.24 7.15 8.05 9.43 10.4

1.72 2.49 3.50 5.19 7.76 10.4

7.73 8.73 10.0 11.3 13.2 14.6

26.8 56.3 104 237 493 889

S-P-F

38 38 38 38 38 38

x x x x x x

89 114 140 184 235 286

1.27 1.83 2.58 3.82 5.71 7.69

5.17 5.85 6.70 7.55 8.84 9.78

1.77 2.57 3.61 5.35 8.00 10.8

7.24 8.19 9.38 10.6 12.4 13.7

23.4 49.3 91 .2 207 432 778

Northern

38 38 38 38 38 38

x x x x x x

89 114 140 184 235 286

0.814 1.18 1.66 2.45 3.67 4.94

4.48 5.07 5.81 6.54 7.66 8.48

1.14 1.65 2.32 3.44 5.14 6.92

6.28 7.10 8.13 9.16 10.7 11.9

16.7 35.2 65.2 148 308 556

D.Fir-L

38 38 38 38 38 38

x x x x x x

89 114 140 184 235 286

0.768 1.11 1.56 2.32 3.46 4.66

6.55 7.41 8.49 9.57 11.2 12.4

1.07 1.56 2.19 3.24 4.85 6.53

9.18 10.4 11 .9 13.4 15.7 17.3

24.6 51 .6 95.6 217 452 815

Hem-Fir

38 38 38 38 38 38

x x x x x x

89 114 140 184 235 286

0.844 1.22 1.72 2.55 3.81 5.13

5.52 6.24 7.15 8.05 9.43 10.4

1.18 1.71 2.41 3.57 5.33 7.18

7.73 8.73 10.0 11.3 13.2 14.6

24.6 51.6 95.6 217 452 815

S-P-F

38 38 38 38 38 38

x x x x x x

89 114 140 184 235 286

0.906 1.31 1.85 2.73 4.09 5.50

5.17 5.85 6.70 7.55 8.84 9.78

1.27 1.84 2.58 3.83 5.72 7.70

7.24 8.19 9.38 10.6 12.4 13.7

21 .2 44.6 82.5 187 390 704

Northern

38 38 38 38 38 38

x x x x x x

89 114 140 184 235 286

0.583 0.844 1.19 1.76 2.63 3.54

4.48 5.07 5.81 6.54 7.66 8.48

0.817 1.18 1.66 2.46 3.68 4.96

6.28 7.10 8.13 9.16 10.7 11 .9

15.6 32.8 60.8 138 288 519

Species Select Structural

System Case 2

2

-~~

- '

Note: For Case 1 System multiply single member Mr and Vr values by 1.10.

40

Bending Members

Joist Selection Tables Sawn Lumber Single member

System Case 2

Esl

Vr

Mr

Vr

kN-m

kN

kN-m

kN

x10 9 N-mm 2

Size (b x d) Mr Select Structural

NO.1/No.2

Species

mm

D.Fir-L

64 64 64 64 64 64

x x x x x x

89 114 140 184 235 286

2.13 3.09 4.35 6.44 9.62 13.0

11 .0 12.5 14.3 16.1 18.9 20.9

2.99 4.32 6.09 9.01 13.5 18.1

15.5 17.5 20.0 22.6 26.4 29.2

47.0 98 .8 183 415 865 1560

Hem-Fir

64 64 64 64 64 64

x x x x x x

89 114 140 184 235 286

2.07 2.99 4.21 6.24 9.33 12.6

9.30 10.5 12.0 13.6 15.9 17.6

2.90 4.19 5.90 8.74 13.1 17.6

13.0 14.7 16.9 19.0 22.2 24.6

45.1 94.8 176 399 831 1500

S-P-F

64 64 64 64 64 64

x x x x x x

89 114 140 184 235 286

2.13 3.09 4.35 6.44 9.62 13.0

8.71 9.85 11.3 12.7 14.9 16.5

2.99 4.32 6.09 9.01 13.5 18.1

12.2 13.8 15.8 17.8 20.8 23.1

39.5 83.0 154 349 727 1310

Northern

64 64 64 64 64 64

x x x x x x

89 114 140 184 235 286

1.37 1.98 2.79 4.13 6.18 8.32

7.55 8.54 9.78 11 .0 12.9 14.3

1.92 2.78 3.91 5.79 8.65 11 .7

10.6 12.0 13.7 15.4 18.1 20.0

28.2 59.3 110 249 519 936

D.Fir-L

64 64 64 64 64 64

x x x x x x

89 114 140 184 235 286

1.29 1.87 2.63 3.90 5.83 7.85

11 .0 12.5 14.3 16.1 18.9 20.9

1.81 2.62 3.69 5.46 8.16 11.0

15.5 17.5 20.0 22.6 26.4 29.2

41.4 86.9 161 365 761 1370

Hem-Fir

64 64 64 64 64 64

x x x x x x

89 114 140 184 235 286

1.42 2.06 2.90 4.29 6.41 8.64

9.30 10.5 12.0 13.6 15.9 17.6

1.99 2.88 4.06 6.01 8.98 12.1

13.0 14.7 16.9 19.0 22.2 24.6

41.4 86.9 161 365 761 1370

S-P-F

64 64 64 64 64 64

x x x x x x

89 114 140 184 235 286

1.53 2.21 3.11 4.60 6.88 9.27

8.71 9.85 11 .3 12.7 14.9 16.5

2.14 3.09 4.35 6.44 9.63 13.0

12.2 13.8 15.8 17.8 20.8 23.1

35.7 75.1 139 316 658 1190

Northern

64 64 64 64 64 64

x x x x x x

89 114 140 184 235 286

0.980 1.42 2.00 2.96 4.43 5.97

7.55 8.54 9.78 11.0 12.9 14.3

1.30 1.99 2.80 4.15 6.20 8.35

10.6 12.0 13.7 15.4 18.1 20.0

26.3 55.3 102 233 485 873

Note: For Case 1 System multiply single member Mr and Vr values by 1.10.

41

Wood Design Manual

Joist Selection Tables Sawn Lumber

Species Select Structural

D.Fir-L

Single member

System Case 2

M,

V,

M,

V,

kN

kN-m

kN

x109 N-mm 2

15A

4.15

18.5 21.3 24.3 28.6 31 .9

6A1 9.07 13.6 20A 27.7

21 .5 25.9 29.8 34.0 40.1 44.7

65A 137 254 578 1200 2170

Size (b x d) kN-m mm 89 89 89 89 89 89

x x x x x x

89 114 140 184 235 286

2.97 4.58

6A8 9.69 14.6 19.8

Esl

to

Hem-Fir

18.1 21.8 25.1 28.6 33.7 37.6

62.7 132 244 554 1160 2080

4.15

6A8 9.69 14.6 19.8

12.1 14.6 16.8 19.2 22.6 25.2

17.0 20.5. 23.5 26.8 31 .6 35.3

54.9 115 214 485 1010 1820

89 114 140 184 235 286

1.91 2.94 4.16 6.23 9.38 12.7

10.5 12.7 14.6 16.6 19.6 21.8

2.67 4.12 5.82 8.72 13.1 17.8

14.7 17.7

30.6

39.2 82A 153 347 722 1300

x x x x x x

89 114 140 184 235 286

1.80 2.78 3.92 5.88 8.85 12.0

15A 18.5 21 .3 24.3 28.6 31 .9

2.52 3.89 8.23

12A 16.8

21.5 25.9 29.8 34.0 40.1 44.7

57.5 121 224 508 1060 1910

89 89 89 89 89 89

x x x x x x

89 114 140 184 235 286

1.98 3.05 4.32 6.46 9.73 13.2

12.9 15.6 17.9 20.4 24.1 26.9

2.77 4.27 6.04 9.05 13.6 18.5

18.1 21.8 25.1 28.6 33.7 37.6

57.5 121 224 508 1060 1910

89 89 89 89 89 89

x x x x x x

89 114 140 184 235 286

2.12 3.28 4.63 6.93

12.1 14.6 16.8 19.2 22.6 25 .2

2.97 4.59

6A8 9.71 14.6 19.8

17.0 20.5 23.5 26.8 31.6 35.3

49.7 104 193 439 914 1650

89 89 89 89 89 89

x x x x x x

89 114 140 184 235 286

1.37 2.11 2.98

10.5 12.7 14.6 16.6 19.6 21 .8

1.91 2.95 4.18 6.25 9.41 12.8

14.7 17.7

36.6 76.9 142 323 674 1210

x x x x x x

89 114 140 184 235 286

2.88 4A4 6.28 • 9AO 14.2 19.2

89 89 89 89 89 89

x x x x x x

89 114 140 184 235 286

2.97 4.58

89 89 89 89 89 89

x x x x x x

89 89 89 89 89 89

Hem-Fir

S-P-F

S-P-F

Northern

No.1/No.2

4.03 6.22 8.79 13.2 19.8 26.9

89 89 89 89 89 89

D.Fir-L

Northern

10A 14.2

4A7 6.72 9.13

12.9 15.6 17.9

20A 24.1 26.9

6A1 9.07 13.6 20A 27.7

5A9

Note: For Case 1 System multiply single member M, and V, values by 1.10.

20A 23.2

27A

20A 23.2 27.4 30.6

Q.

5'

(Q

3: d)

KN = 1-~ d

(if e < d)

KN =

1-

r

dn e d (d - dn )

where: d dn e

= depth of beam (mm) = depth of notch (mm), which must not exceed O.25d = length of notch (mm), from inner edge of closest support to farthest edge of notch

Cv is a shear load coefficient. The tables are based on a simply supported beam with a uniformly distributed load, therefore C v =3.69. If the beam is not simply supported or the loading is not uniformly distributed, select the appropriate Cv value from Clause 6.5.7.4 of CSA 086 and multiply the tabulated Wr LO.18 value by Cv / 3.69.

Table 2.9 Effective length L. for bending members

Beams

Intermediate support Yes No

Any loading

1.92 a

Uniformly distributed load

1.92 a

1.92lu 1.92 lu

Concentrated load at centre

1.11 a

1.61 1u.

Concentrated loads at 1/3 points

1.68 a

Concentrated loads at 1/4 points

1.54 a

Concentrated loads at 1/5 points

1.68 a

Concentrated loads at 1/6 points

1.73 a

1n points

1.78 a

Concentrated loads at 1/8 points

1.84 a

Concentrated loads at

Cantilevers Any loading Uniformly distributed load

1.23 III

Concentrated load at free end where: lu = unsupported length = distance between points of bearing or the length of the cantilever, mm. a = maximum purlin spacing when purlins provide lateral support for the compressive edge of the beam, mm.

2

58

Table 2.10 Values of KL for glulam beams

Bending Members

24f-E stress grade

20f-E stress grade

Cb

D.Fir-L

Spruce-Pine

D.Fir-L, Hem-Fir

10 12 14 16 18 20 22 24 26 28

1.00 0.969 0.942 0.901 0.841 0.758 0.651 0.547 0.466 0.402 0.350 0.307 0.272 0.243 0.218 0.197 0.178 0.163 0.149 0.137 0.126

1.00 0.955 0.916 0.857 0.770 0.654 0.540 0.454 0.387 0.334 0.291 0.255

1.00 0.960 0.926 0.873

30 32 34 36 38 40 42 44 46 48 50

Notes: 1. C b = ~L.d / b 2 where L.

0.226 0.202 0.181 0.163 0.148 0.135 0.124 0.114 0.105

0.575 0.483 0.412 0.355 0.309 0.272 0.241 0.215 0.193 0.174 0.158 0.144 0.132 0.121 0.111

= effective length, mm (Table 2.9); d = depth, mm; b = width, mm.

2. KL values are valid when KD CSA086.

= KH = Ks = 1.0. For other conditions, use Clause 6.5.6.4.4 of

3. Use the lesser of KL and KZbg to determine Mr .

."

0.797 0.691

59

Wood Design Manual

Table 2.11 Values of KZbg for glulam beams

B(mm) L m

80

130

175

215

265

315

365

1

0.986

1

3 3.5

0.988

0.962

0.998

0.967

0.942

4 4.5

0.979

0.949

0.924

5.5

1

0.962

0.933

0.909

6

0.984

0.948

0.918

0.894

Ul

6.5

0.970

0.934

0.905

0.882

CD

5

7

0.993

0.957

0.922

0.893

0.870

7.5

0.981

0.945

0.910

0.882

0.859

8

0.969

0.934

0.900

0.872

0.849

8.5

0.959

0.924

0.890

0.863

0.840

9

1

0.949

0.915

0.881

0.854

0.831

9.5

0.992

0.940

0.906

0.872

0.846

0.823

10

0.982

0.931

0.897

0.864

0.838

0.816

10.5

0.974

0.923

0.890

0.857

0.830

0.809

11

0.966

0.915

0.882

0.850

0.824

0.802

11 .5

0.958

0.908

0.875

0.843

0.817

0.796

12

0.951

0.901

0.868

0.836

0.811

0.790

12.5

0.944

0.895

0.862

0.830

0.805

0.784

13

0.937

0.888

0.856

0.824

0.799

0.778

13.5

0.931

0.882

0.850

0.819

0.794

0.773

14

0.925

0.877

0.845

0.813

0.789

0.768

14.5

1

0.919

0.871

0.839

0.808

0.784

0.763

15

0.997

0.913

0.866

0.834

0.803

0.779

0.758

Notes: 1. B is the member width for single piece laminations, mm. For laminations consisting of multiple pieces, B is the width of the widest piece. Glulam laminations wider than 175 mm are typically constructed with multiple pieces. Check with glulam supplier. 2. L is the length of the glulam from point of zero moment to zero moment, m. For simple span beams, L is the span of the beam . 3. K Zgb = 1.03(B/l 000 x L)-o.18 but not greater than 1.0. 4. Use the lesser of K Zbg and KL to determine Mr'

til

CD

"5'Co 3:

3

C"

CD

iil

60

Bending Members

Example 1: Beams

Design single span floor beams for the following conditions: o o o o o o o o

beam spacing =3.0 m beam span = 6.0 m specified dead load = 1.5 kPa (includes partitions and self weight) specified live load = 2.4 kPa (commercial use and occupancy) gypsum ceiling standard load duration dry service condition untreated

Use D.Fir-L NO.1 sawn timber. Calculation

Tributary area =3.0 x 6.0 = 18.0 m2 < 20.0 m2 Therefore, no live load reduction is permitted by the NBCC. Total Factored Load = (1.25 x 1.5) + (1.5 x 2.4) = 5.48 kPa Total Specified Load = 1.5 + 2.4 = 3.90 kPa

wL

= 5.48 x 3.0 = 16.4 kN/m = 3.90 x 3.0 = 11.7 kN/m = 2.40 x 3.0 =7.20 kN/m

M,

=

w, L2 8

V,

=

w,L 2

w, w

=

16.4 x 6.0 2 8 16.4 x 6.0 2

=

73.8 kNLm

49.2 kN

For U180 deflection limit based on total load:

= 180 [5 w L3]

180 [5 x 11 .7 x 6000 384

=

384

3]

=5920 X 109 N omm2 For U360 deflection limit based on live load: 3

3

= 360 [5 w L L 384

]

=

360 [5 x 7.20 x 6000 384

=7290 x 109 N omm 2

t

]

(governs stiffness calculation)

Wood Design Manual

61

From Beam Selection Tables for sawn timber try 241 x 394 mm:

Mr

= 79.8 kN-m > 73.8 kN-m

Acceptable

Vr = 76.9 kN > 49.2 kN

Acceptable

Use 241 x 394 mm No.1 D.Fir-L. Example 2: Beams Design single span floor beams for the following conditions: • • • •

beam spacing = 5.0 m beam span = 7.5 m specified dead load = 2.0 kPa (includes partitions and self-weight) specified live load = 2.4 kPa (office area above first floor) gypsum ceiling

• • •

standard load duration dry service condition untreated compression edge assumed fully laterally supported by joists framed in by joist hangers and spaced at 400 mm on centre.

Use D.Fir-L 20f-E glulam .

Calculation Tributary area = 5.0 x 7.5 =37.5 m2 > 20 m r--2_ _ _ Live load reduction factor (LLRF) = 0.3 + (9.8/37.5) = 0.81 (from Article 4.1.6.9, NBCC)

J

Live Load = 2.4 x 0.81 = 1.94 kPa Total Factored Load = (1.25 x 2.0) + (1.5 x 0.81 x 2.4) = 5.42 kPa Total Specified Load = 2.0 + (2.4 x 0.81) = 3.94 kPa w

= 5.42 x 5.0 =27.1 kN/m = 3.94 x 5.0 = 19.7 kN/m

wL

=

WI

1.94 x 5.0

= 9.7 kN/m

2

62

Bending Members

Mf =

Wf L2 8

Vf =

wfL 2

27.1 x 7.5 2 =

8 27.1x7.5 2

191kN om

102 kN

For Ll180 deflection limit based on total load: 3

= 180 [5WL

3 ] =

384

180 [5X19.7X7500 384

= 19500 x 109 N omm 2

]

(governs stiffness calculation)

For Ll360 deflection limit based on live load: 3

= 360 [5 w L L 384

3 ] =

360 [5 x 9.7 x 7500 384

]

= 19200 x 109 N omm 2 From Beam Selection Tables for glulam try 130 x 646 mm: M'r

=

208 KNom

Mr

= = = =

lesser of M'r KL or M'r KZb9 1 (compression edge laterally supported)

KL KZb9 Mr

1 (Table 2.11) 208 kN om > 191 kN om

Acceptable

For beam volumes < 2 m3 , Vr may be used as a simplified method of checking shear resistance. beam volume Vr

= 101

=0.630 m3

kN < 102 kN

Not Acceptable

For beams < 2 m3 , Wr may be used to check beam shear capacity. For beam volumes ~ 2 m3 , Wr must be used to check beam shear capacity. Calculate Wr and compare to W f to check shear resistance: Wr Wf Esl

= 418 x (7.5)·0.18 = 291 kN = 27.1 x 7.5 =203 kN = 36200 x 109 N omm2 > 19500 x 109 N omm2

Note: Verify acceptable bearing capacity as per Chapter 6

Use 130 x 646 mm 20f-E D.Fir-L glulam.

Acceptable Acceptable

63

Wood Design Manual

Beam Selection Tables Sawn Timbers Select Structural

Mr

Vr

No.2 Grade

No.1 Grade

Esl

Mr

Vr

x10 9

Esl

Mr

Vr

x 10 9

Esl x1 0 9

Size (b x d) mm kN'm

kN

N·mm 2

kN·m

kN

N·mm 2

kN·m

kN

N·mm 2

140 140 140 140 140 140

x 140 x 191 x 241 x 292 x 343 x 394

9.79 18.2 28.5 38.4 48.2 57.2

22.9 31 .3 36.4 40.5 43.2 44.7

384 976 1960 3490 5650 8560

7.38 13.7 23.1 31 .1 39.0 46.4

22.9 31 .3 36.4 40.5 43.2 44.7

336 854 1960 3490 5650 8560

3.21 5.98 13.2 17.7 22.2 26.4

22.9 31 .3 36.4 40.5 43.2 44.7

304 772 1550 2760 4470 6780

140 140 140 140 140 140

x 140 x 191 x 241 x 292 x 343 x 394

7.28 13.5 21.2 28.6 35.8 42.5

18.3 25.0 29.2 32.4 34.6 35.7

320 813 1630 2900 4710 7140

5.46 10.2 17.1 23.0 28.9 34.3

18.3 25.0 29.2 32.4 34.6 35.7

288 732 1630 2900 4710 7140

2.41 4.48 9.81 13.2 16.6 19.7

18.3 25.0 29.2 32.4 34.6 35 .7

256 650 1310 2320 3770 5710

S-P-F

140 x 140 140 x 191 140 x 241

6.80 12.6 19.9

18.3 25.0 29.2

272 691 1390

5.14 9.56 16.1

18.3 25.0 29.2

240 610 1390

2.25 4.18 9.22

18.3 25.0 29.2

208 528 1060

Northern

140 x 140 140 x 191 140 x 241

6.42 12.0 18.7

15.3 20.9 24.3

256 650 1310

4.82 8.96 15.1

15.3 20.9 24.3

224 569 1310

2.09 3.88 8.64

15.3 20.9 24.3

192 488 980

D.Fir-L

191 x 191 191 x241

191 x 292 191 x 343 191 x 394

24.9 36.5 52.4 65.7 78.1

42.7 49.7 55.2 59.0 61 .0

1330 2670 4760 7710 11700

18.8 27.6 42.5 53.3 63.2

42.7 49.7 55.2 59.0 61.0

1160 2340 4760 7710 11700

8.15 12.0 24.2 30.3 36.0

42.7 49.7 55.2 59.0 61.0

1050 2120 3760 6100 9250

Hem-Fir

191 191 191 191 191

x 191 x 241 x 292 x 343 x 394

18.5 27.2 39.0 48.9 58.0

34.1 39.8 44.2 47.2 48.8

1110 2230 3960 6420 9740

13.9 20.4 31.4 39.4 46.8

34.1 39.8 44.2 47.2 48.8

998 2010 3960 6420 9740

6.11 8.99 18.0 22.6 26.8

34.1 39.8 44.2 47.2 48.8

887 1780 3170 5140 7790

S-P-F

191 x 191 191 x 241

17.3 25.3

34.1 39.8

943 1890

13.0 19.1

34.1 39.8

832 1670

5.71 8.38

34.1 39.8

721 1450

Northern

191 x 191 191 x 241

16.3 24.0

28.5 33.1

887 1780

12.2 18.0

28.5 33.1

776 1560

5.30 7.79

28.5 33.1

665 1340

Species D.Fir·L

Hem-Fir

2

aJ

CD :::I Co

s·

(Q

3: CD 3 r:T

~ In

64

Bending Members

Beam Selection Tables Sawn Timbers Select Structural

Mr

Mr

Vr

kN

Esl x109 N-mm 2

kN-m

62.7 69.7 74.4 76.9

3370 6000 9730 14700

34.8 46.8 67.2 79.8

34.3 46.1 61 .7 73.2

50.2 55.7 59.5 61 .5

2810 5000 8100 12300

241 x 241

32.0

50.2

Northern

241 x 241

30.2

D.Fir-L

292 292 292 343 343 394

x x x x x x

292 343 394 343 394 394

Hem-Fir

292 292 292 343

x x x x

292 343 394 343

No.2 Grade

Mr

Vr

kN

Esl x109 N-mm 2

kN-m

kN

Esl x109 N-mm 2

62.7 69.7 74.4 76.9

2950 5250 9730 14700

15.1 20.3 38.3 45.5

62.7 69.7 74.4 76.9

2670 4750 7700 11700

25.7 34.6 49.8 59.1

50.2 55.7 59.5 61 .5

2530 4500 8100 12300

11 .3 15.3 28.5 33.8

50.2 55.7 59.5 61 .5

2250 4000 6480 9830

2390

24.2

50.2

2110

10.6

50.2

1830

41 .8

2250

22.7

41 .8

1970

9.83

41 .8

1690

75.2 94.3 119 111 132 151

84.4 90.1 93.2 106 110 126

7270 11800 17900 13800 21000 24100

56.7 71.1 96.7 83.5 99.2 114

84.4 90.1 93.2 106 110 126

6360 10300 17900 12100 18400 21100

24.6 30.9 55.1 36.3 43.1 49.5

84.4 90.1 93.2 106 110 126

5760 9330 14100 11000 16600 19100

55.9 70.1 88.7 82.3

67.5 72.1 74.6 84.7

6060 9820 14900 11500

41 .9 52.6 71.6 61 .7

67.5 72.1 74.6 84.7

5450 8840 14900 10400

18.5 23.2 41 .0 27.2

67.5 72.1 74.6 84.7

4850 7860 11900 9230

Size (b x d) kN-m mm

D.Fir-L

241 241 241 241

x x x x

241 292 343 394

46.1 62.0 82.9 98.5

Hem-Fir

241 241 241 241

x x x x

241 292 343 394

S-P-F

Species

Vr

No.1 Grade

Wood Design Manual

65

Beam Selection Tables Glulam Spruce-Pine 20f-E Stress Grade W,LO.18 M', V,

Esl x109

Size (b x d)

mm

kN·m kN

kN·mO.18 N·mm 2

80 80 80 80 80

3.99 7.10 11 .1 16.0 21 .7

59.3 75.0 90.1 105 119

x 114 x 152 x 190 x 228 x 266

D.Fir-L 20f-E Stress Grade W,LO.18 M' , V,

9.58 12.8 16.0 19.2 22.3

102 241 471 814 1290

Esl

D.Fir-L 24f-E Stress Grade W,LO.18 M', V,

x109

Esl

kN·m kN

kN·mO.18 N·mm 2

kN·m kN

x 109 kN·mO.18 N·mm 2

3.99 7.10 11 .1 16.0 21 .7

67.7 85.7 103 120 136

4.77 8.48 13.3 19.1 26.0

67.7 85.7 103 120 136

10.9 14.6 18.2 21.9 25.5

122 290 567 980 1560

10.9 14.6 18.2 21 .9 25.5

129 307 599 1040 1640

tD 98.3 kN

Acceptable

b) For the cantilevered beams select 130 x 722 mm: M'r

= 260 kN-m

In this case, KL is not equal to 1 since the lower edge of the cantilevered beam is in compression along part of its length and will not be fully supported. The maximum unsupported length is found to be 2.14 m at the ends of the interior span. Using Tables 2.9 and 2.10, KL is calculated to be 0.95. From a bending moment diagram L, the length from zero moment to zero moment, was found to be 7.71 m. Using Table 2.11, KZb9 = 1. Therefore: Mr

= 260 x 0.95 = 248 kN"m > 203 kN"m

Acceptable

Wood Desig n Manual

89

7. Check shear on the cantilevered beam. Vr = 113 kN < 132 kN

Not Acceptable

Therefore, check Wr:

WI = 2 x 98.3 + (19 .2 x 15.5) = 494 kN Cv = 6.61 (From Table 6.5.7.4C of CSA 086) 18

Wr = 458 (15.5r o.

CD

[6.61] =501 kN >494 kN 3.69

Acceptable

ID

:::J

Q.

:r

CD

3:

ID

8. Check deflection at the centre of the cantilevered beam. This occurs when full snow load extends over the centre span and half of full snow load on the outside spans. Maximum allowable deflection is governed by U180 based on total load. Using the deflection formulae in Chapter 11 : !l

=

L\max

=

33 mm L 180

12000 = 66.7 mm >33 mm 180

Acceptable

9. Check deflection of the suspended beam . This occurs when full snow load is on the suspended beam and supporting cantilever, and half of full snow load on the other spans. Using the deflection formulae in Chapter 11 : !l

=

~max

=

deflection of suspended beam + 112 deflection of cantilever = 42 mm L = 67 mm >42 mm 180

Acceptable

Use 130 x 722 mm glulam for the cantilevered beam and the suspended beams.

3 aID Ul

90

Bending Members

Compression Members

3.1 3.2 3.3 3.4

General Information ........ .... ....... 95 Stud Walls and Posts .................. 97 Columns . .......................... 111 Built-up Columns .................... 141

3

92

Compression Members

Wood Design Manual

Wood columns are elegantly integrated into this version of a post and beam frame for a clubhouse structure.

Stud grade lumber is used together with plywood sheathing in bearing wall applications such as this gable wall.

93

94

Continuous columns form an integral part of this attractive glulam frame .

Heavy loads are supported by this spaced glulam column. A unique architectural detail is used for the base shoe shown to transfer the loads to the foundation .

Compression Members

Wood Design Manual

3.1

95

General Information The following sections contain design information for members that are used in compression parallel to grain. These members include sawn lumber studs, posts, truss chords, single member glulam and sawn timber columns, and nailed built-up sawn lumber columns. The design information is for concentrically loaded members ; however, the designer must consider eccentricity where it occurs. Chapter 5 provides design information for members subjected to bending due to eccentricity or lateral loading combined with compression. In addition , Chapter 6 provides design information for compression perpendicular to grain. Selection tables are arranged to provide compressive resistances , Pr' for given species, grades and sizes. Checklists are given in each section. The designer should review these checklists to be sure that the tabulated resistance is appropriate for the actual conditions of use.

&>

3

'tI

iii III III

o· :::I 3: C1I 3

g in

9~6_ _ _Compression _ _. ~Members

97

Wood Design Manual

3.2

Stud Walls and Posts General

Lumber products are produced in accordance with CSA Standard 0141 Softwood Lumber. The characteristics of structural grades are outlined in the National Lumber Grades Authority Standard Grading Rules for Canadian Lumber. "Stud" grade lumber, which is manufactured specifically for use in stud wall systems, is assigned the same strength values as No.3 grade lumber, but other grades may also be used. Sawn lumber used in stud wall systems has a common thickness of 38 mm and ranges in depth from 89 to 184 mm. Stud grade lumber, however, ranges in depth from 38 to 140 mm; the smaller sizes are used mainly in partitions. For depths greater than 140 mm , another grade must be specified . In stud walls, the members are spaced no farther apart than 610 mm to take advantage of load-sharing. Usually the spacing is 406 mm or less. Stud wall systems are usually sheathed by plywood, waferboard, oriented strandboard or drywall. The sheathing is nailed to the narrow faces of the studs (on at least one side) along the entire length of the stud, thereby preventing buckling about the weak axis. Studs are susceptible to buckling if heavy loads are applied prior to installation of the sheathing. Members supporting stud walls or posts must provide adequate bearing resistance to prevent crushing. Bearing considerations are covered in Chapter 6. For walls with combined vertical and lateral loading, refer to Chapter 5. Shearwall design considerations are covered in Chapter 9 and fire resistance ratings for stud wall assemblies are discussed in Chapter 10. Sawn lumber posts are generally 89 x 89 mm or larger No.1 grade members. Posts may also be built up from 38 mm lumber (refer to Section 3.4) . Availability

The Stud Wall Selection Tables provide design information for the sizes and grades shown in Table 3.1 . Table 3.1 Grades, available sizes and common stud and post sizes for sawn lumber

Grade Available sizes Common stud and post sizes (mm) -----------------------------Select Structural, 38 to 89 mm in thickness 38 x 89 No.1, No.2, No.3 and 38 to 286 mm in depth 38 x 140 38 x 184

Stud

38 to 89 mm in thickness and 38 to 140 mm in depth

89 x 89 38 x 89 38 x 140

S-P-F, Hem-Fir and D.Fir-L are most likely to be stocked by lumber yards, but species in the Northern species combination may also be on hand. Lumber can usually be obtained kiln- or air-dried to a moisture content of 19% or less (specify S-Dry) in 38 mm thickness. The 64 and 89 mm thicknesses are generally surfaced in the green condition (S-Grn).

3 oo 3

"tI

Cil

III III

ci" ::J 3: CD 3

g til

98

Compression Members

Design Sawn lumber members subjected to axial loading must be designed so that the following criterion is satisfied: Factored compressive resistance parallel to grain Pr compressive load Pf

O!:

factored

The factored compressive resistance, Pr , may be determined as follows: 1. When the conditions of use meet the requirements given in the following checklist, Pr may be taken directly from the Stud Wall Selection Tables.

2. When the conditions of use do not meet the requirements of the checklist, the value of Pr given in the selection tables is not valid. Furthermore, the tabulated values cannot be adjusted by a factor that will apply throughout the entire unsupported length range. Therefore, Pr should be calculated from the following formula. This formula may also be used for lumber sizes not given in the selection tables. Pr where:

=

16.4 kN = 32.4 kN > 16.4 kN

Acceptable Acceptable

Use 38 x 140 mm Stud grade S-P-F sawn lumber at 600 mm spacing.

Wood Design Manual

101

Example 2: Stud Wall Systems Check the bearing wall in Example 1 for wet service conditions.

Calculation

Fe A KZe Kc

4.25 MPa from Table 3.2

Kzc

=

=5320 mm 2 6.3 (140 x 3000)-0.13 = 1.17

Cc

=

3000/140 = 21.4

Fe / E'

=

29.4 x 10-6 from Table 3.3

Kc

=

=

[1.0 + 29.4 x 10-6 x 1.17 x (21.4)3J-1 0.748

=

4.25 x 5320 x 1.17 x 0.748 19.8 kN > 16.4 kN

38 x 140

Or(wet)

Acceptable

=

Or (dry) KSep

= =

32.4 kN x 0.67

(refer to Chapter 6)

21.7kN>16.4kN

Acceptable

38 x 140 mm Stud grade S-P-F studs can be used under wet service conditions provided sheathing is adequate for wet service.

102

Compression Members

Figure 3.1 Effective length factor for compression members

Degree of end restraint of compression member

Effective length factor K.

Effectively held in position and restrained against rotation at both ends

0.65

Effectively held in position at both ends, restrained against rotation at one end

0.80

Effectively held in position at both ends, but not restrained against rotation

1.00

Effectively held in position and restrained against rotation at one end, and at the other restrained against rotation but not held in position

1.20

Effectively held in position and restrained against rotation at one end, and at the other partially restrained against rotation but not held in position

1.50

Effectively held in position at one end but not restrained against rotation , and at the other end restrained against rotation but not held in position

2.00

Symbol

I

1 [

rr,

1.-,_1 I

/'

1..,_1 I

/'

r-' ,,

... .... _1

I

/'

Effectively held in position and restrained against rotation at one end but not held in position nor restrained against rotation at the other end

2.00

I"


~

C1I

3

g iii

104

Compression Members

Stud Wall Selection Tables Sawn Lumber Factored compressive resistance per stud P, (kN) D.Fir-L

Select Structural

L m

d mm 89

140

184

89

140

184

89

140

184"

2.0 2.2 2.4 2.6 2.8

36.1 30.8 26.2 22.2 18.9

87.6 81.4 75.1 69.0 63.1

126 120 115 110 104

28.1 24.2 20.7 17.7 15.1

65.9 61.6 57.2 52.8 48.6

93.6 89.9 86.2 82.3 78.4

12.8 11 .7 10.5 9.47 8.47

24.3 23.3 22.4 21.4 20.4

32.4 31 .6 30.8 30.0 29.2

3.0 3.2 3.4 3.6 3.8

16.2 13.9 11.9 10.3 8.98

57.5 52.3 47.4 43.0 38.9

98.3 92.6 87.0 81.6 76.3

13.0 11.2 9.64 8.36 7.28

44.5 40.7 37.1 33.7 30.7

74.4 70.4 66.4 62.5 58.7

7.55 6.73 5.99 5.34 4.76

19.3 18.3 17.3 16.3 15.3

28.3 27.5 26.6 25.7 24.7

4.0 4.2 4.4 4.6 4.8

7.84 6.88 6.06

35.2 31 .9 28.9 26.2 23.8

71 .2 66.4 61 .8 57.5 53.4

6.37 5.59 4.94

27.9 25.3 23.0 20.9 19.0

55.0 51 .5 48.1 44.9 41 .9

4.25 3.80 3.40

14.4 13.4 12.6 11.7 10.9

23.8 22.9 21 .9 21 .0 20.1

5.0 5.2 5.4 5.6 5.8

21.6 19.7 18.0 16.4 15.0

49.6 46.1 42.8 39.8 36.9

17.4 15.8 14.5 13.2 12.1

39.0 36.4 33.9 31.5 29.4

10.2 9.51 8.86 8.25 7.69

19.2 18.3 17.5 16.6 15.8

6.0 6.2 6.4 6.6 6.8 7.0

13.8 12.6 11.6 10.7 9.88 9.14

34.3 31.9 29.7 27.7 25.8 24.1

11.1 10.2 9.43 8.70 8.04 7.44

27.4 25.5 23.8 22.2 20.7 19.4

7.17 6.68 6.23 5.82 5.43 5.08

15.1 14.3 13.6 12.9 12.2 11 .6

42.8

56.3

42.8

56.3

42.8

56.3

Q,(kN)

27.2

No.1INo.2

27.2

No.31Stud

27.2

Note: Tabulated values are valid for the following conditions : • standard term loading (dead plus snow or occupancy) • dry service conditions • untreated lumber, or preservative treated but not incised • studs effectively pinned and laterally restrained at both ends and prevented from buckling about weak axis by wall sheathing • wall system consisting of at least 3 studs spaced no farther apart than 610 mm apart • studs concentrically loaded * 38 x 184 mm lumber is available as No.3, but not as Stud grade.

105

Wood Design Manual

Stud Wall Selection Tables Sawn Lumber Factored compressive resistance per stud Pr (kN) No.1INo.2

NO.31Stud

Hem-Fir

Select Structural

L m

d mm 89

140

184

89

140

184

89

140

184'

2.0 2.2 2.4 2.6 2.8

34.7 29.8 25.4 21 .7 18.5

82.4 76.8 71 .2 65.6 60.3

117 113 108 103 97.8

29 .9 25.8 22.0 18.8 16.1

69.9 65.3 60.6 56.1 51.6

99.0 95.2 91.3 87.2 83.1

17.6 15.7 13.9 12.2 10.7

35.7 34.0 32.3 30.5 28.7

48.6 47.2 45.8 44.3 42.8

3.0 3.2 3.4 3.6 3.8

15.9 13.7 11 .8 10.2 8.88

55.1 50.3 45.8 41.6 37.8

92.8 87.7 82.6 77.7 72.9

13.8 11.9 10.3 8.94 7.78

47.3 43.2 39.4 35.9 32.7

78.9 74.7 70.5 66.4 62.4

9.43 8.28 7.28 6.41 5.65

27.0 25.2 23.5 21.9 20.3

41.2 39.7 38.1 36.5 34.8

4.0 4.2 4.4 4.6 4.8

7.77 6.82 6.01

34.3 31 .1 28.2 25.7 23.3

68.2 63.7 59.5 55.5 51 .7

6.81 5.99 5.28

29 .7 27.0 24.5 22.3 20.3

58.5 54.8 51 .2 47.8 44.6

5.00 4.44 3.95

18.8 17.4 16.1 14.9 13.7

33.2 31 .6 30.1 28.5 27.1

5.0 5.2 5.4 5.6 5.8

21 .2 19.4 17.7 16.2 14.8

48.1 44.8 41 .6 38.7 36.1

18.5 16.9 15.5 14.2 13.0

41.6 38.7 36.1 33.6 31.3

12.7 11 .7 10.8 10.0 9.26

25.6 24.2 22.9 21.6 20.4

6.0 6.2 6.4 6.6 6.8 7.0

13.6 12.5 11 .5 10.6 9.80 9.07

33.6 31 .3 29.1 27.2 25.4 23.7

11.9 11 .0 10.1 9.31 8.60 7.96

29.2 27.2 25.4 23.7 22.1 20.7

8.58 7.95 7.37 6.84 6.36 5.92

19.2 18.1 17.1 16.1 15.2 14.3

28.1

37.0

28.1

37.0

28.1

37.0

0

Q,(kN)

17.9

17.9

17.9

Note : Tabulated values are valid for the following conditions : • standard term loading (dead plus snow or occupancy) • dry service conditions • untreated lumber, or preservative treated but not incised • studs effectively pinned and laterally restrained at both ends and prevented from buckling about weak axis by wall sheathing • wall system consisting of at least 3 studs spaced no farther apart than 610 mm apart • studs concentrically loaded , 38 x 184 mm lumber is available as No.3, but not as Stud grade ,

0

3

"iil 1/1 1/1

o·;:, s: co 3

c:r

co

Ci1

106

Compression Members

Stud Wall Selection Tables Sawn Lumber Factored compressive resistance per stud Pr (kN) S-P-F

Select Structural

L m

d mm B9

140

1B4

B9

140

1B4

B9

140

1B4'

2.0 2.2 2.4 2.6 2.B

29.6 25.5 21.9 1B.7 16.0

6B.7 64.3 59.7 55.3 50.9

97.2 93.5 B9.7 B5.7 B1.7

24.4 21.2 1B.3 15.7 13.5

55.4 51.9 4B.5 45.1 41 .7

77.6 74.B 72.0 69.0 65.9

17.0 15.1 13.3 11 .7 10.2

35.3 33.6 31 .B 29.9 2B.1

4B.3 46.9 45.4 43.9 42.3

3.0 3.2 3.4 3.6 3.B

13.B 11.9 10.3 B.90 7.76

46.7 42.B 39.0 35.6 32.4

77.7 73.6 69.5 65.5 61 .6

11 .7 10.1 B.73 7.60 6.63

3B.4 35.3 32.3 29.6 27.0

62.B 59.7 56.6 53.5 50.4

B.91 7.BO 6.B3 6.00 5.2B

26.3 24.5 22.7 21.1 19.5

40.7 39.0 37.4 35.7 34.0

4.0 4.2 4.4 4.6 4.B

6.79 5.97 5.27

29.5 26.B 24.4 22.2 20.2

57.B 54.2 50.7 47.3 44.2

5.B2 5.12 4.52

24.7 22.5 20.5 1B.7 17.1

47.5 44.6 41.B 39.2 36.7

4.66 4.13 3.67

1B.0 16.6 15.3 14.1 13.0

32.4 30.B 29 .2 27.6 26.1

5.0 5.2 5.4 5.6 5.B

1B.4 16.B 15.4 14.1 12.9

41 .2 3B.4 35.B 33.4 31.1

15.6 14.3 13.1 12.0 11.0

34.3 32.1 30.0 2B.0 26.1

12.0 11 .0 10.2 9.40 B.6B

24.6 23.2 21.9 20.6 19.4

6.0 6.2 6.4 6.6 6.B 7.0

11 .9 10.9 10.1 9.2B B.5B 7.94

29.0 27.1 25.2 23.6 22.0 20.6

10.1 9.33 B.61 7.95 7.35 6.B1

24.4 22.B 21.3 19.9 1B.7 17.5

B.02 7.43 6.BB 6.3B 5.92 5.50

1B.3 17.2 16.2 15.2 14.3 13.5

32.4

42.6

32.4

42.6

32.4

42.6

No.1INo.2

NO.31Stud

-

-

~

Qr(kN)

20.6

1-

~

20.6

-

,-

~-

I '~~

20.6

Note : Tabulated values are valid for the following conditions: • standard term loading (dead plus snow or occupancy) • dry service conditions • untreated lumber, or preservative treated but not incised • studs effectively pinned and laterally restrained at both ends and prevented from buckling about weak axis by wall sheathing • wall system consisting of at least 3 studs spaced no farther apart than 610 mm apart • studs concentrically loaded , 3B

x

1B4 mm lumber is available as No.3, but not as Stud grade,

Wood Design Manual

107

Stud Wall Selection Tables Sawn Lumber Factored compressive resistance per stud P, (kN) Northern

Select Structural

No.1INo.2

L m

d mm 89

140

184

89

140

184

89

140

184'

2.0 2.2 2.4 2.6 2.8

24.0 20.4 17.3 14.6 12.4

59.3 54.9 50.5 46.3 42.2

85.5 81 .8 78.0 74.2 70.2

20.5 17.6 15.0 12.8 10.9

48.6 45.3 42.0 38.7 35.5

69.3 66.5 63.7 60.7 57.8

11.4 10.2 9.07 8.01 7.05

23.1 22.0 20.9 19.8 18.6

31 .3 30.4 29.5 28.6 27.6

3.0 3.2 3.4 3.6 3.8

10.6 9.07 7.80 6.74 5.85

38.4 34.8 31.5 28.5 25.7

66.3 62.3 58.4 54.7 51.0

9.35 8.04 6.93 6.01 5.23

32.5 29.6 27.0 24.5 22.2

54.8 51 .7 48.8 45.8 43.0

6.20 5.45 4.80 4.23 3.74

17.5 16.4 15.3 14.3 13.3

26.7 25.7 24.7 23.6 22.6

4.0 4.2 4.4 4.6 4.8

5.10 4.47 3.94

23.2 21 .0 19.0 17.2 15.6

47.5 44.2 41.1 38.2 35.4

4.57 4.01 3.54

20.2 18.3 16.6 15.1 13.7

40.2 37.6 35.1 32.7 30.4

3.31 2.94 2.62

12.3 11.4 10.6 9.76 9.03

21 .6 20.6 19.6 18.6 17.6

5.0 5.2 5.4 5.6 5.8

14.2 12.9 11.7 10.7 9.80

32.8 30.4 28.2 26.2 24.3

12.5 11.4 10.4 9.53 8.73

28.3 26.4 24.5 22.8 21.2

8.35 7.72 7.14 6.61 6.12

16.7 15.8 15.0 14.1 13.4

6.0 6.2 6.4 6.6 6.8 7.0

8.97 8.23 7.57 6.97 6.43 5.94

22.6 21 .0 19.5 18.1 16.9 15.7

8.01 7.36 6.77 6.25 5.77 5.34

19.8 18.4 17.2 16.0 14.9 13.9

5.67 5.25 4.88 4.53 4.21 3.92

12.6 11.9 11 .2 10.6 10.0 9.43

21.4

28.1

21.4

28.1

21.4

28.1

No.31Stud

0

Q,(kN)

13.6

13.6

13.6

Note : Tabulated values are valid for the following conditions: • standard term loading (dead plus snow or occupancy) • dry service conditions • untreated lumber, or preservative treated but not incised • studs effectively pinned and laterally restrained at both ends and prevented from buckling about weak axis by wall sheathing • wall system consisting of at least 3 studs spaced no farther apart than 610 mm apart • studs concentrically loaded , 38 x 184 mm lumber is available as No.3, but not as Stud grade,

0

3 Cil

..

"C

ci" :::I

3:::

'3"

i

in

108

Compression Members

Checklist: Posts To verify that the tabulated resistances given in the Post Selection Table are adequate for the structure being designed , the following questions should be asked : 1. Is the load duration "standard" term (dead load plus snow load or occupancy loads)? 2. Is the service condition "dry"? 3. Is the material free of strength reducing chemicals such as fire retardants? 4. Is the effective length factor Ke equal to 1.0 or 2.0 as shown in the Post Selection Table? If the answer to any of these questions is no, the Post Selection Table may not be used. Instead, calculate Pr from the formulae given on page 98. Example 3: Post Check the resistance of a single 89 x 89 mm No.1/No.2 grade S-P-F post for the following conditions: • • • •

specified dead load = 1.5 kPa specified live load = 2.4 kPa tributary area =4.5 m2 unbraced length = 3.0 m

• dry service conditions • untreated • post effectively pinned at both ends Calculation Total factored load: Pf = (1 .25 x 1.5 + 1.5 x 2.4 ) x 4.5 = 24.6 kN

From the Post Selection Table: Pr

= 26.6> 24.6 kN

The 89 x 89 mm No.1/No.2 grade S-P-F Post is adequate.

Acceptable

Compression Members

109

109

Post Selection Table Sawn Lumber Factored compressive resistance per post Pr (kN) D.Fir-L

Hem-Fir

S-P-F

Northern

L

m where K. 1.0 1.5 2.0 2.5 3.0 3.5 4.0 where K. 1.0 1.5 2.0

Sel Str

No.l/No.2

Sel Str

No.l/No.2

Sel Str

No.l/No.2

Sel Str

No.l/No.2

140 112 80.6 54.7 37.0 25.6 18.2

104 85.1 62.6 43.2 29.6 20.7 14.7

131 106 77.4 53.2 36.3 25.2 18.0

110 90.3 66.6 46.1 31 .6 22.1 15.8

108 88.9 65.8 45.7 31 .5 22.0 15.7

86.7 72.1 54.3 38.2 26.6 18.7 13.4

95.2 75.4 53.7 36.1 24.3 16.7 11 .8

77.2 62.5 45.7 31 .3 21.4 14.9 10.6

= 1.0

(')

o 3 iii rn

'C

= 2.0 80.6 37.5 18.3

62.6 30.0 14.9

77.4 36.8 18.2

66.6 32.0 15.9

65.8 31.9 15.9

54.3 26.9 13.6

53.7 24.6 11 .9

45.7 21 .6 10.7

o·rn

::J

s:

C1I

3

Note: Tabulated values are valid for the following conditions: • standard term loading (dead plus snow or occupancy) • dry service conditions • untreated lumber • Ke = 1.0 or K. = 2.0 • L = unsupported length • concentrically loaded

K.= 1.0

K. = 2.0

g iil

r, !

110

.~

II' •.i '!

Compression Members

111

Wood Design Manual

3.3

Columns General

This section provides design procedures and selection tables for two types of wood columns: • Sawn timbers • Glued-laminated timber (glulam) Sawn timbers are produced in accordance with CSA Standard 0141 Softwood Lumber. The rules for the grading of timbers are outlined in the National Lumber Grades Authority Standard Grading Rules for Canadian Lumber. Generally, timber columns fall into the Post and Timber size and end use category. Glued-laminated timber is an engineered wood product manufactured by gluing together 38 or 19 mm thick lumber laminations with a waterproof adhesive. Glulam is manufactured to meet CSA Standard 0122 Structural GluedLaminated Timber and the manufacturers of glulam must be certified in accordance with CSA Standard 0177 Qualification Code for Manufacturers of Structural Glued-Laminated Timber. Generally, the 16c-E or 12c-E stress grade is used for compression members. The 24f-EX and 2Of-EX grades are used for members subjected to combined axial and bending loads and design information is provided in Chapter 5. Availability Sawn Timber The Column Selection Tables for sawn timber provide resistance values for the following grades and sizes: Table 3.4 Grades and sizes of sawn timber columns

Grades

Column sizes for all grades (mm)

Select Structural, No.1, No.2

140 x 140 191 x 191 241 x 241 292 x 292 140x191 191 x 241 241 x 292

D.Fir-L and Hem-Fir are the species groups most readily available in lumber yards, but S-P-F and Northern species may also be obtained. All the sizes listed above should be available; however, the availability of large sizes should be checked before specifying. Timbers may be obtained in lengths up to 9.1 m, but this should also be confirmed with local suppliers. The most readily available grades are No.1 and No.2 but Select Structural may be ordered.

b' 3

"tJ

iii OJ

o·OJ

:::I

;c I'D

3

:6

ii1

112

Compression Members

Timbers are always dressed green as their large size makes kiln-drying impractical. As a result, some amount of shrinkage and checking can be expected after dressing. These effects should be considered when detailing members and connections.

Glulam The Column Selection Tables for glulam provide resistance values for the following species, grades and thicknesses:

!i Table 3.5 Species, grades and thicknesses of glulam columns

Species and stress grades

D.Fir-L: 16c-E Spruce-Pine: 12c-E

Column thickness for all species and grades mm

80 130 175 215 265 315 365

II "

,

I

Most fabricators produce either D.Fir-L or Spruce-Pine glulam. The thicknesses shown in Table 3.5 are industry standards, but some fabricators can produce slightly different sizes. Most fabricators use 38 mm thick laminations for straight columns. Design Sawn timber and glulam columns subjected to axial loading must be designed so that the following criterion is satisfied: Factored compressive resistance parallel to grain Pr compressive load PI

~

factored

The factored compressive resistance, Pr , may be determined as follows: 1. When the conditions of use meet the restrictions listed in the following checklist, Pr may be taken directly from the Column Selection Tables for sawn timber or glulam. 2. When the conditions of use do not meet the requirements of the checklist, the value of Pr given in the selection tables is not valid. Furthermore, the tabulated values cannot be adjusted by a factor that will apply throughout the entire unsupported length range. Therefore, Pr should be calculated from the following formula:

113

Wood Design Manual

Pr

= Fe A Kze Kc

(N)

where:

Fe

= factored compressive strength (MPa) , given in Table 3.6 for sawn timber and Table 3.8 for glulam

A Kze

= cross-sectional area (mm2) = size factor for sawn timber KZe 6.3 (d Ld )-O.13 < 1.3 for buckling in direction of d 6.3 (b L b)"o.13 < 1.3 for buckling in direction of b

= =

for glulam KZe 0.68 (Z) -O.13 < 1.0, where Z

=

Kc

=

Fe / E'

[1.0 +

E~ KZe C~ ]

:::I

g-

-1

(jl

= strength to stiffness ratio , given in K L

K L

d

b

~ or ~

= the greater of

Ke

= effective length factor, given in Figure 3.1 = unsupported length associated with d or b (mm) = depth of member (mm) = thickness of member (mm)

b

o· 3

Ce

d

3 til

III III

."

Table 3.7 for sawn timber and Table 3.9 for glulam

Ld , Lb

0

"C

3:

slenderness factor F

=

= member volume in m 3

0

(C e > 50 is not permitted)

Since column design is an iterative process, the Column Selection Tables may be used to select a trial section . When designing a sawn timber column with an effective length factor Ke other than 1.0 or 2.0, a preliminary section may be selected by using the table for Ke = 1.0 with the length L equal to the actual effective length KeL. The preliminary section can then be checked using the formula above (note the difference between the estimated resistance and the actual resistance will not usually exceed 5%).

114

Compression Members

Additional Design Considerations Where a column must be drilled or notched , the cross-sectional area removed must not exceed 25% of the gross area of the member (refer to Section 7.1 for information on net area) . As long as the drilling or notching does not occur near the point of maximum buckling stress, the tabulated resistances given in the following sections may not need to be adjusted. However, the designer should check the resistance at net section assuming an unsupported length of zero. In certain cases the National Building Code of Canada (NBCC) permits the loads due to use and occupancy to be reduced depending upon the size of the tributary area the member supports. Refer to Article 4.1.6.9 of the NBCC for the appropriate reduction factor. Example 1: Sawn Timber Columns Design columns for the following conditions : • • • •

specified dead load = 2.0 kPa specified live load = 2.4 kPa tributary area = 25 m2 unbraced length = 5 m

• dry service conditions • untreated • column effectively pinned at both ends (Ke = 1.0) Use No.1 D.Fir-L. Calculation Tributary area> 20 m2 Therefore, live load reduction factor from Part 4 of the NBCC is:

=

0.3 +

~ 9.8 25

=

0.926

Total factored load : PI

= (1 .25 x 2.0 + 1.5 x 0.926 x 2.4) x 25 = 146 kN

From Column Selection Tables select 191 x 191 mm : Pr

= 186 kN > 146 kN

Use 191 x 191 mm No.1 D.Fir-L column.

Acceptable

Wood Design Manual

115

Checklist: Columns To verify that the tabulated resistances given in the Column Selection Tables are appropriate for the structure being designed, the following questions should be asked:

3

1. Is load duration "standard" term (dead load plus snow or occupancy loads)? 2. Is the service condition "dry"? (')

o

3. Is the material free of strength reducing chemicals such as fire retardants?

3

"(i!

U> U>

4. For sawn timber columns only: Is the effective length factor Ke equal to 1.0 or 2.0 as shown in the Column Selection Tables? For glulam columns only: Is the effective length factor Ke equal to 1.0 and the effective column length in the direction of buckling equal to the total column length? 5. Are the columns concentrically loaded? If the answer to any of these questions is no, the Column Selection Tables may not be used. Instead, calculate Pr from the formula given on page 113. Information on eccentrically loaded columns is provided in Chapter 5. Example 2: Sawn Timber Columns Design a column for the following conditions : • • • • •

specified dead load = 1.0 kPa specified live load = 1.9 kPa specified snow load = 2.0 kPa tributary area = 25 m2 (for both snow and live load) unbraced length 5 m

=

• wet service conditions • treated with a preservative • column effectively pinned at both ends (Ke = 1.0) Use No.2 D.Fir-L. Calculation Live load reduction factor = 0.926

o·

:>

;: CD

3

gin

II

116

Compression Members

Total factored load: PI = (1.25 x 1.0 + 1.5 x 0.926 x 1.9 + 0.5 x 2.0) x 25 = 122 kN or PI

= (1.25 x 1.0 + 0.5 x 0.926 x 1.9 + 1.5 x 2.0) x 25 = 128 kN

Governs

Since service conditions are wet, the Column Selection Tables cannot be used to select final size. However, the selection tables may be used to obtain a trial section. Select 191 x 191 mm as a trial section since it is the smallest section with Pr > 128 kN. Calculate Pr for wet service conditions:

Pr

128 kN

=

Acceptable

Use a 191 x 191 mm No.2 D. Fir-L column. Example 3: Glulam Columns

Is a 175 x 228 mm 12c-E Spruce-Pine glulam column adequate for the following conditions? • • • •

specified dead load = 1.5 kPa specified snow load =3.5 kPa tributary area =30 m2 total length = 7 m

• dry service condition • untreated The column is effectively pinned at both ends and braced at mid-height in the narrow dimension as shown below.

Wood Design Manual

117

Buckled shape - - : (about Yaxis) "

3.5 m

,

175mm

xi x

228 mm

,, ,, ,, ,,, ,

Y 3.5 m

Calculation Since the column supports dead plus snow loads only, the NBCC live load reduction factor does not apply. Total factored load:

Pf

= (1.25 x 1.5 + 1.5 x 3.5) x 30 = 214 kN

Slenderness ratio, Cc

Ccx Ccy

= Ke x Ld / d = 1.0 x 7000/228 =30.7

Governs

= Ke x Lb / b = 1.0 x 3500 / 175 = 20.0

Since buckling about X axis governs, Column Selection Tables may be used because Ke Ld = L. From Column Selection Tables:

Prx = 217kN>214kN

Acceptable

The 175 x 228 mm 12c-E Spruce-Pine glulam section is adequate.

118

Compression Members

Example 4 : Glulam Columns Is a 175 x 228 mm Spruce-Pine glulam column adequate for the following conditions? • • • •

= =

specified dead load 1.5 kPa specified snow load 3.5 kPa tributary area 30 m 2 total length = 9 m

=

• dry service conditions • untreated The column is effectively pinned at both ends and braced at mid-height in all directions.

Calculation Although the effective length factor Ke is equal to 1.0 in both X and Y directions, the Column Selection Tables cannot be used because the effective column length about X and Y axis (Ke x Ld,b = 1.0 x 4.5 = 4.5 m) is not equal to the total column length (L = 9.0 m). Total factored load:

= (1.25 x 1.5 + 1.5 x 3.5 ) x 30

Pf

= 214 kN

Calculate Pr Pr

Fe

:

= Fe A KZe Kc = 20.16 MPa from Table 3.8

A

= 175 x 228 = 39.9 x 103 mm 2

KZc

=

0.68 x (0.175 x 0.228 x 9.0)-0.13

= 0.78

Fe / E'

= 85.32 x 10-6 from Table 3.9

C ex

= 1.0 x 4500/228 = 19.7

C ey

=

Kc

= [1.0 + 85.32 x 10-6 x 0.78 x (25.7)3J-1 = 0.47

1.0 x 4500 / 175

= 25.7 (governs)

= 20.2 x 39.9 x 103 x 0.78 x 0.47 = 295 kN > 214 kN

Acceptable

The 175 x 228 mm 12c-E Spruce-Pine glulam section is adequate.

119

Wood Design Manual

Table 3.6 Factored compressive strength for sawn timbers ~ Fe (MPa)'

Service conditions Load duration 2 Species D.Fir-L

Hem-Fir

S-P-F

Northern

Wet service

Dry service Std.

Perm .

Short term

Std .

Perm.

Short term 11.6

Grade Sel Str

11 .0

7.18

12.7

10.0

6.53

No.1

9.76

6.34

11 .2

8.88

5.77

10.2

No.2

6.00

3.90

6.90

5.46

3.55

6.28

Sel Str

9.04

5.88

10.4

8.23

5.35

9.46

No.1

8.00

5.20

9.20

7.28

4.73

8.37

No.2

4.88

3.17

5.61

4.44

2.89

5.11

Sel Str

7.92

5.15

9.11

7.21

4.68

8.29

No.1

6.96

4.52

8.00

6.33

4.12

7.28

No.2

4.32

2.81

4.97

3.93

2.56

4.52

Sel Str

6.00

3.90

6.90

5.46

3.55

6.28

No.1

5.36

3.48

6.16

4.88

3.17

5.61

No.2

3.28

2.13

3.77

2.98

1.94

3.43

Notes: 1. For fire-retardant treated material , multiply by a treatment factor KT. See the Commentary for further guidance. 2. Standard term loading = dead loads plus snow or occupancy loads Permanent loading = dead loads alone Short term loading = dead plus wind loads 3. Fe = fe KD KH KSe KT (refer to Clause 5.5.6 of CSA 086) . 4. Sawn timbers have a smaller dimension of at least 114 mm and a larger dimension not more than 51 mm greater than the smaller dimension.

Table 3.7 Strength to stiffness ratio for sawn timbers Fe I E' (x10-6)

Service conditions Load duration' Species D.Fir-L

Hem-Fir

S-P-F

Northern

Dry service Std.

Wet service

Perm.

Short term

Std .

Perm.

Short term

Grade Sel Str

49.3

32.0

56.7

44.9

29.2

51.6

No.1

53.6

34.9

61 .7

48.8

31 .7

56.1 37.4

No.2

35.7

23.2

41.1

32.5

21 .1

Sel Str

46.1

30.0

53.0

42.0

27.3

48.3

No.1

47.6

31.0

54.8

43.3

28.2

49.8

No.2

31 .7

20.6

36.4

28.8

18.7

33.2

Sel Str

47.1

30.6

54.2

42.9

27.9

49.3

No.1

49.7

32.3

57.2

45.2

29.4

52.0

No.2

34.3

22.3

39.4

31.2

20.3

35.9 40.8

Sel Str

39.0

25.3

44.8

35.5

23.0

No.1

38.3

24.9

44.0

34.8

22.6

40.1

No.2

29.3

19.0

33.7

26.7

17.3

30.6

Notes: 1. Standard term loading = dead loads plus snow or occupancy loads Permanent loading = dead loads alone Short term loading = dead plus wind loads 2. Fe IE' = (fe KD KH Kse KT) 1(35 E 05 KSE KT) (refer to Clause 5.5.6 of CSA 086) .

(")

0

...,3 Cil

In In

cr::I 3: ell

3 cr ell

;;;

120

Compression Members

Table 3.8 Factored compressive strength for glulam Fe (MPa)

Service conditions

Dry service

Wet service

Std.

Perm .

Short term

D.Fir-L 16c-E

24.2

15.7

27.8

Spruce-Pine 12c-E

20.2

13.1

23 .2

Load duration 2

Perm.

Short term

18.1

11 .8

20.8

15.1

9.83

17.4

Std.

Compression grades

Notes : 1. For fire-retardant treated material, multiply by a treatment factor Kr See the Commentary for further guidance. 2. Standard term loading = dead loads plus snow or occupancy loads Permanent loading = dead loads alone Short term loading = dead plus wind loads 3. Fe = fe KD KH Kse KT (refer to Clause 6.5.8 of CSA 086).

Table 3.9 Modified strength to stiffness ratio for glulam Fe / E' (x10-6)

Service conditions Load duration 1

Dry service Std.

Wet service

Perm .

Short term

Std.

Perm.

Short term

Compression grades D.Fir-L 16c-E

80.0

52.0

92.0

66.7

43.3

76.7

Spruce-Pine 12c-E

85.3

55.5

98.1

71.1

46.2

81.8

Notes: 1. Standard term loading = dead loads plus snow or occupancy loads Permanent loading = dead loads alone Short term loading = dead plus wind loads 2. Fe / E' = (fe KD KH Kse KT) / (35 E05 KSE KT) (refer to Clause 6.5.8 of CSA 086).

121

Wood Design Manual

Column Selection Tables Sawn Timbers Square timbers b(mm) d (mm) D.Fir-L Select Structural

{[ K. = 1.0

rr '----(-'

L

}

I

/

L

/'

,, /

/

K. = 2.0

191 191

241 241

292 292

140 191

191 241

241 292

L m

Pr

Pr

Pr

Pr

Prx

Pry

Prx

Pry

Prx

Pry

kN

kN

kN

kN

kN

kN

kN

kN

kN

kN

2.0 2.5 3.0 3.5 4.0

227 194 162 132 106

447 411 373 333 293

714 675 634 590 545

1040 992 947 902 854

328 301 273 244 215

309 265 220 180 145

566 535 502 468 432

564 519 470 420 369

856 819 782 744 705

865 817 768 715 660

4.5 5.0 5.5 6.0 6.5

85.3 68.5 55.3 44.9 36.8

255 219 188 161 138

498 452 406 364 324

804 752 699 646 595

187 161 138 118 101

116 93.5 75.4 61.3 50.2

395 358 322 288 257

321 277 238 203 174

663 620 577 533 491

603 547 492 440 392

7.0 7.5 8.0 8.5 9.0

30.4

118 101 86.9 75.1 65.1

287 255 225 200 177

545 497 452 411 372

86.3 74.1 63.7 55.1 47.7

41.5

228 202 179 158 140

149 127 110 94.8 82.2

449 410 373 339 307

348 308 273 242 214

2.0 2.5 3.0 3.5 4.0

110 70.3 45.7 30.8

311 230 167 121 88.6

585 480 382 299 233

920 810 688 575 473

228 168 122 88.6 65.0

151 95.9 62.4 42.0

464 380 303 237 184

392 290 210 152 112

763 667 568 474 391

709 582 463 362 282

66.1

181 142 113 90.5

387 315 258 212 175 145

48.4

144 113 89.5 71.7

83.4

319 260 213 175 144 120

220 173 137 110

1' -

(

L

140 140

~

Rectangular timbers

/

", , , ,

/' V /

4.5 5.0 5.5 6.0 6.5 7.0

Notes: 1. Prx is the factored resistance to buckling about the x-x (strong) axis. Pry is the factored resistance to buckling about the y-y (weak) axis. 2. For L :s 2.0 m, use Pr for L = 2.0 m. Where Pr values are not given , the slenderness ratio exceeds 50 (maximum permitted) . 3. Tabulated values are valid for the following conditions : • standard term load (dead plus snow or occupancy loads) • dry service conditions • no fire-retardant treatment • Ke = 1.0 or Ke = 2.0 • concentrically loaded .

3

Compression Members

122

Column Selection Tables Sawn Timbers Rectangular timbers

Square timbers b(mm) d (mm) D.Fir-L No.1

{[ K. = 1.0

L

I----

'- -;--' /

I

I

-

-

I

I" I

I

I

-

241 241

292 292

140 191

191 241

241 292

P,

P,

P,

P,

P",

Pry

P",

Pry

Prx

Pry

kN

kN

kN

kN

kN

kN

kN

kN

kN

kN

2.0 2.5 3.0 3.5 4.0

198 168 138 112 89.5

393 360 324 288 251

629 593 556 515 474

915 874 834 791 747

288 264 238 211 184

270 229 189 153 122

499 470 440 409 375

496 454 409 363 317

756 722 688 653 617

763 719 673 625 574

4.5 5.0 5.5 6.0 6.5

71 .3 57.0 45.8 37.1 30.3

217 186 159 135 115

431 389 348 310 274

701 653 605 557 510

159 136 116 99.0 84.3

97.3 77.8 62.5 50.6 41 .3

341 308 276 245 217

274 235 200 170 145

578 539 499 460 421

522 471 421 375 332

7.0 7.5 8.0 8.5 9.0

25.0

98.0 83.8 71 .9 62.0 53.6

242 214 189 167 147

465 423 383 347 313

71 .8 61.4 52.7 45.4 39.3

34.1

192 170 150 132 117

124 106 90.7 78.2 67.7

384 349 316 286 259

294 259 229 202 178

2.0 2.5 3.0 3.5 4.0

92.8 58.4 37.7 25.3

266 194 140 100 73.2

508 412 325 252 195

808 701 592 490 400

195 143 102 73.6 53.7

127 79.6 51.4 34.5

403 327 258 200 154

336 245 176 127 92.4

667 578 489 405 330

616 500 394 305 236

54.4

151 118 93.1 74.4

325 263 214 175 144 120

39.9

120 93.4 73.8 58.9

68.6

268 217 177 145 119 98.7

183 143 113 90.1

' - 1-

(,

I

191 191

L m

/

I'

L

140 140

K. = 2.0

,,"

",

'"

I

4.5 5.0 5.5 6.0 6.5 7.0

Notes: 1. P", is the factored resistance to buckling about the x-x (strong) axis. Pry is the factored resistance to buckling about the y-y (weak) axis. 2. For L s 2.0 m, use P, for L = 2.0 m. Where P, values are not given , the slenderness ratio exceeds 50 (maximum permitted). 3. Tabulated values are valid for the following conditions : • standard term load (dead plus snow or occupancy loads) • dry service conditions • no fire-retardant treatment • K. = 1.0 or Ke 2.0 • concentrically loaded.

=

b

Iv1

xill} y

123

Wood Design Manual

Column Selection Tables Sawn Timbers Square timbers b(mm) d(mm) D.Fir-L

No.2

{[ K. =1.0

{!::T

140 140

191 191

Rectangular timbers

241 241

292 292

140 191

191 241

241 292

L m

P,

P,

P,

P,

P",

Pry

P",

Pry

P",

Pry

kN

kN

kN

kN

kN

kN

kN

kN

kN

kN

2.0 2.5 3.0 3.5 4.0

129 113 97.5 82.3 68.4

247 231 213 194 175

391 373 353 334 312

566 544 523 501 479

181 169 156 142 128

175 155 133 112 93.3

310 295 280 264 248

312 291 269 245 221

467 449 431 414 395

474 451 428 404 379

4.5 5.0 5.5 6.0 6.5

56.4 46.3 38.1 31.4 26.0

156 138 121 105 91.5

291 268 246 224 203

456 432 407 382 357

114 101 88.4 77.1 67.1

76.9 63.2 51 .9 42.8 35.5

230 213 195 178 161

197 174 152 133 115

376 357 336 315 295

352 325 298 272 246

7.0 7.5 8.0 8.5 9.0

21 .7

2.0 2.5 3.0 3.5 4.0

71 .6 47.8 32.1 22.0

79.6 69.2 60.2 52.5 46.0

184 165 148 133 119

332 307 284 261 240

58.3 50.7 44.1 38.5 33.7

29.6

187 145 110 82.1 61.7

337 287 237 192 154

520 466 409 353 299

137 106 80.3 60.2 45.2

97.6 65.2 43.8 30.1

46.8

123 98.7 79.4 64.4

251 210 175 146 122 103

34.3

145 131 118 106 94.7

100 87.3 76.0 66.3 58.0

274 254 234 216 198

222 200 180 161 145

267 227 188 153 122

236 183 138 104 77.8

429 385 338 291 247

409 348 288 233 187

97.7 78.2 62.9 51.0

59.1

207 173 144 120 101 84.7

149 120 96.2 78.0

1-

r-

I" ,

//

L

/

/

I

"-

K.

=2.0

,

' ...

,

/' ' / /

4.5 5.0 5.5 6.0 6.5 7.0 Notes:

1. P,x is the factored resistance to buckling about the x-x (strong) axis. Pry is the factored resistance to bucklin g about the y -y (weak axis. 2. For L s 2.0 m, use P, for L =2.0 m. Where P, values are not given, the slenderness ratio exceeds 50 (maximum permitted) . 3. Tabulated values are valid for the following conditions: • standard term load (dead plus snow or occupancy loads) • dry service conditions • no fire-retardant treatment • Ke = 1.0 or Ke =2.0 • concentrically loaded .

3 (")

o

3

"tI

Cil

rn rn

('j"

::s

s::

3

g iil

124

Compression Members

-Hem-Fir Select Structural

{[ K. = 1.0

{IT [I

L

/

/

/

K. = 2.0

c", , ,, / /

/'

V

/

Column Selection Tables Sawn Timbers Square timbers b(mm) d(mm)

140 140

191 191

Rectangular timbers

241 241

292 292

140 191

191 241

241 292

L m

P,

P,

P,

P,

P",

Pry

P",

Pry

P",

Pry

kN

kN

kN

kN

kN

kN

kN

kN

kN

kN

2.0 2.5 3.0 3.5 4.0

187 162 135 111 90.3

368 339 309 277 245

586 554 522 488 452

850 814 778 742 704

270 249 226 203 179

256 220 185 152 123

464 439 414 386 358

464 428 389 349 309

702 672 642 613 581

710 672 632 591 547

4.5 5.0 5.5 6.0 6.5

72.8 58.8 47.6 38.8 31.9

214 185 160 137 118

414 377 341 306 274

665 623 582 539 498

157 136 117 101 86.3

99.4 80.2 65.0 52.9 43.5

328 299 270 243 217

270 234 202 173 149

549 515 480 445 411

502 457 413 371 332

7.0 7.5 8.0 8.5 9.0

26.4

101 86.9 75.0 64.9 56.4

244 217 192 171 152

457 419 382 348 317

74.1 63.7 54.9 47.5 41.3

36.0

193 172 152 135 120

128 110 94.6 81 .9 71 .1

378 346 315 287 261

295 263 233 207 184

2.0 2.5 3.0 3.5 4.0

93.9 60.4 39.5 26.7

260 194 142 104 76.5

486 402 322 254 199

763 670 575 483 401

191 143 104 76.1 56.1

128 82.3 53.9 36.4

385 318 255 201 158

328 245 179 131 96.5

630 553 475 399 331

589 487 391 308 241

57.2

156 123 97.6 78.4

329 270 221 182 151 126

41 .9

124 97.3 77.4 62.1

72.2

272 223 183 150 125 104

189 149 118 95.0

"

4.5 5.0 5.5 6.0 6.5 7.0

I ~~

Notes: 1. P", is the factored resistance to buckling about the x-x (strong) axis. Pry is the factored resistance to buckling about the y-y (weak) axis. 2. For L s; 2.0 m, use P, for L = 2.0 m. Where P, values are not given, the slenderness ratio exceeds 50 (maximum permitted). 3. Tabulated values are valid for the following conditions: • standard term load (dead plus snow or occupancy loads) • dry service conditions • no fire-retardant treatment • K. = 1.0 or Ke = 2.0 • concentrically loaded.

125

Wood Design Manual

Column Selection Tables Sawn Timbers Square timbers b(mm) d (mm)

140 140

191 191

Rectangular timbers

241 241

292 292

140 191

191 241

241 292

Hem-Fir No.1

L m

P,

P,

P,

P,

Prx

Pry

P rx

Pry

P rx

Pry

kN

kN

kN

kN

kN

kN

kN

kN

kN

kN

L~[

2.0 2.5 3.0 3.5 4.0

165 142 119 97.0 78.5

325 299 272 243 214

518 490 461 430 397

752 720 688 655 621

238 219 199 178 157

225 193 162 132 107

410 388 365 341 315

410 377 343 307 271

621 594 568 541 513

628 593 558 521 481

4.5 5.0 5.5 6.0 6.5

63.2 50.9 41.1 33.5 27.5

187 162 139 119 102

364 331 298 267 239

585 548 511 473 436

137 119 102 87.3 74.8

86.2 69.4 56.1 45.7 37.5

288 262 236 212 189

236 204 175 150 129

483 453 422 390 360

441 401 361 324 289

K.

=1.0

(')

o

3

...o·

'tl

iil :::I

3:

CD

r

I ,- I'

'--;--'

L

/

I

/

"-

/

L

/

/

I

"-

K.

22.7

2.0 2.5 3.0 3.5 4.0

81.6 52.2 34.1 23.0

-

/

B:

50 is not permitted)

C

cd

= Ke L d C = Ke L b - dcb b

L d , Lb

= unsupported length associated with total member depth d or width b (mm)

b

= total width of column , which is the thickness of an individual ply multiplied by the number of plies (mm)

d

= depth of column , wh ich is the depth of an individual ply (mm)

m

III

is" :::I ;s:

.. 3

i

iil

144

Compression Members

Where the column is short, or where sheathing prevents buckling about the weak axis of the plies, Pr may calculated as the combined factored resistance of the individual pieces taken as independent members. This will provide a larger factored resistance than calculated from the formula given above for these cases. The resistance of an individual piece may be calculated from the design formula given in Section 3.1. Example 1: Built-up Columns Design a built-up column for the following conditions : • • • •

specified dead load = 1.0 kPa specified snow load = 2.4 kPa tributary area = 9 m2 unsupported length = 3 m

• dry service cond itions • untreated • column effectively pinned at both ends Use Stud grade S-P-F. Calculation Total factored load: PI

= (1 .25 x 1.0 + 1.5 x 2.4) x 9 = 43.6 kN

From Built-up Column Selection Tables select 4-ply 38 Pr

= 62.5 kN > 43.6 kN

x

140 mm: Acceptable

Use 4-ply 38 x 140 mm Stud grade S-P-F built-up columns nailed together as shown in Figure 3.2.

145

Wood Design Manual

Built-up Column Selection Tables Nailed Built-up Factored compressive resistance P, (kN) D.Fir-L

Grade Select Structural

No.1/No.2

NO.31Stud

S-P-F

Hem-Fir

Northern

L m

2-Ply

3-Ply

4-Ply

2-Ply

3-Ply

4-Ply

2-Ply

3-Ply

4-Ply

2-Ply

3-Ply

4-Ply

2.0 2.2 2.4 2.6 2.8

31 .9 26.6 22.2 18.5 15.5

81 .6 73.6 65.9 58.8 52.3

128 118 101 86.3 73.8

30.9 25.9 21.7 18.2 15.3

77.3 70 63 56.4 50.4

120 113 98 84.1 72 .1

26.5 22.3 18.8 15.8 13.3

64.9 59.0 53.4 48.0 43.0

99 .6 94.4 84.1 72.4 62.3

21 .1 17.5 14.6 12.1 10.1

54.9 49.3 44.0 39 .1 34.7

86.7 78.4 66.8 56.9 48.5

3.0 3.2 3.4 3.6 3.8 4.0

13.1 11.1 9.46 8.12 7.01

46.4 40.8 35.2 30.5 26.6 23.2

63.2 54.4 47.0 40.7 35.4 31 .0

12.9 11 .0 9.37 8.05 6.96

44.9 39.9 34.7 30.1 26.3 23.0

62.0 53.5 46.3 40.2 35.0 30.7

11 .2 9.57 8.19 7.05 6.10

38.4 34.3 30.2 26.3 22.9 20.1

53.7 46.4 40.3 35.0 30.6 26.8

8.54 7.23 6.16 5.29 4.56

30.7 26.7 23.0 19.9 17.3 15.1

41.5 35.6 30.7 26.6 23.1 20.2

2.0 2.2 2.4 2.6 2.8

25.1 21 .1 17.7 14.8 12.5

62.1 56.4 50.8 45.6 40.8

95.7 90.7 79.6 68.4 58.8

26.7 22.5 18.9 15.8 13.3

65.9 59.9 54.0 48.5 43.4

101 96.1 84.8 72.9 62.7

22.1 18.7 15.8 13.3 11 .3

52.7 48.2 43.8 39.5 35.6

79.9 76.0 70.2 60.7 52.5

18.2 15.3 12.8 10.7 8.99

45.6 41.3 37.2 33.3 29.7

70.7 66.9 57.8 49.5 42.5

3.0 3.2 3.4 3.6 3.8 4.0

10.6 8.98 7.68 6.61 5.71

36.4 32.4 28.4 24.7 21.5 18.9

50.6 43.7 37.8 32.9 28.7 25.2

11 .3 9.60 8.21 7.07 6.11

38.8 34.6 30.3 26.4 23.0 20.2

54.0 46.7 40.4 35.2 30.7 26.9

9.58 8.17 7.01 6.04 5.23

31 .9 28.6 25.6 22.4 19.6 17.2

45.4 39.4 34.2 29.8 26.1 22.9

7.60 6.45 5.51 4.74 4.10

26.4 23.5 20.4 17.7 15.5 13.5

36.5 31.5 27.2 23.7 20.6 18.1

2.0 2.2 2.4 2.6 2.8

12.4 11 .1 9.81 8.63 7.55

24.4 23.1 21 .7 20.4 19.0

34.2 33.1 32.0 30.9 29.7

16.5 14.4 12.5 10.8 9.28

35.2 32.8 30.5 28.1 25.9

50.8 48.8 46.9 44.8 41 .3

15.9 13.8 11 .9 10.2 8.74

34.6 32.1 29.7 27.3 25.0

50.4 48.4 46.3 44.1 39.2

10.8 9.43 8.20 7.09 6.11

22.8 21 .3 19.8 18.3 16.8

32.7 31 .5 30.3 29.0 27.1

3.0 3.2 3.4 3.6 3.8 4.0

6.61 5.79 5.08 4.46 3.93

17.7 16.4 15.1 14.0 12.9 11 .8

28.5 25.9 23.1 20.7 18.5 16.6

8.00 6.92 6.00 5.22 4.56

23.7 21 .6 19.7 17.9 16.3 14.7

36.4 32.1 28.3 25.0 22.1 19.6

7.51 6.47 5.60 4.86 4.24

22.8 20.7 18.8 17.1 15.5 13.7

34.5 30.3 26.6 23.4 20.7 18.3

5.28 4.57 3.97 3.46 3.02

15.5 14.1 12.9 11.8 10.7 9.73

23.9 21 .1 18.7 16.5 14.6 13.0

I-

e_

Notes : 1. Tabulated values are valid for the following conditions : • standard term load (dead load plus snow or occupancy) • dry service conditions • no fire-retardant treatment or preservative treated without incising • column effectively pinned at each end (Ke = 1.0) • concentrically loaded 2. Where values are not given , Cc > 50

,-

o o

3 iil (j)

'1J (j)

5' :I

;;:: 250 kN

Use 80 x 266 mm 14t-E Spruce-Pine glulam.

Acceptable

162

Tension Members

Tension Member Selection Tables Sawn Lumber Factored tensile resistance based on gross area, T, (kN) Machine Stress-Rated (MSR)

Visually graded Size (b x d) Select mm Structural

NO.1/ No.2

NO.3/ Stud

1450Fb 1.3E

1650Fb 1.5E

1800Fb 1.6E

2100F b1.8E

2400Fb2.0E

D.Fir-L

38 38 38 38 38

x x x x x

89 140 184 235 286

48.4 66.0 80.0 93.7 104

26.5 36.1 43.8 51.3 56.7

9.59 13.1 15.9 18.6 20 .5

27.4 43.1 56.6

34.7 54.6 71.7

40.2 63 .2 83.1

53.9 84.7 111

66.1 104 137

Hem-Fir

38 38 38 38 38

x x x x x

89 140 184 235 286

44.3 60.4 73.2 85.8 94.9

28.3 38.6 46.8 54.8 60.6

14.6 19.9 24.2 28.3 31.3

27.4 43.1 56.6

34.7 54.6 71.7

40.2 63.2 83.1

53.9 84.7 111

66.1 104 137

S-P-F

38 38 38 38 38

x x x x x

89 140 184 235 286

39.3 53.5 64.9 76.0 84.1

25 .1 34.2 41 .5 48.6 53 .8

14.6 19.9 24.2 28.3 31 .3

27.4 43.1 56.6

34.7 54.6 71.7

40.2 63.2 83.1

53.9 84.7 111

66.1 104 137

Northern

38 38 38 38 38

x x x x x

89 140 184 235 286

28.3 38.6 46.8 54.8 60.6

18.3 24.9 30.2 35.4 39.1

9.13 12.4 15.1 17.7 19.6

27.4 43.1 56.6

34.7 54.6 71 .7

40.2 63.2 83.1

53.9 84.7 111

66.1 104 137

Species

163

Wood Design Manual

Tension Member Selection Tables Sawn Lumber No.1/No.2

Select Structural

Species D.Fir-L

Hem-Fir

T'N for use with shear plates

T,N for use with shear plates

or split rings (kN)

or split rings (kN)

Size (b x d) mm

T,

2-5/8"

4"

2-1/2"

T,

2-5/8"

4"

2-1/2"

kN

SH If.

SH If.

SR

kN

SH If.

SH If.

SR

64 64 64 64 64

x x x x x

89 140 184 235 286

81.5 111 135 158 175

137

85.7 111 136 155

44.6 60.8 73.8 86.4 95.5

58.9 72.7 83.2

74.7

46.9 60.9 74.6 84.8

64 64 64 64 64

x x x x x

89 140 184 235 286

74.6 102 123 144 160

125

78.4 102 125 142

47.7 65.0 78.9 92.3 102

63.0 77.8 88.9

79.9

50.1 65.1 79.7 90.7

64 64 64 64 64

x 89 x 140 x 184 x 235 x 286

66.1 90.2 109 128 142

111

69.5 90.3 111 126

42.3 57.7 69.9 81.9 90.6

55.9 69.0 78.9

64 64 64 64 64

x x x x x

89 140 184 235 286

47.7 65.0 78.9 92.3 102

79.9

50.1 65.1 79.7 90.7

30.8 41.9 50.9 59.6 65.9

40.6 50.2 57.4

108 133 152

98.5 122 139

..

-4

::I III

c'

::I

S-P-F

Northern

87.3 108 123

63.0 77.8 88.9

.

;;:

70 .9

44.4 57.8 70.7 80.4

51.5

32.3 42.0 51.4 58.5

Notes:

1. T, = Factored tensile resistance based on gross area T'N = Factored tensile resistance based on net area with a single shear plate or split ring on each side of member at a given cross section :

8 2. SH If. = Shear Plate, SR = Split Ring 3. Where T, values are not shown, area removed exceeds 25% of gross area. 4 For 4" diameter shear plates, values are based on the use of 3/4" diameter bolts.

.0 3

CT

164

Tension Members

Tension Member Selection Tables Sawn Lumber Select Structural

No.1INo.2

TrN for use with shear plates or split rings (kN)

Species D.Fir-L

Hem-Fir

S-P-F

Northern

Size (b x d) Tr mm kN

2-5/8" SH ~

89 89 89 89 89

x x x x x

89 140 184 235 286

113 155 187 219 243

119 154 189 215

89 89 89 89 89

x x x x x

89 140 184 235 286

104 141 172 201 222

109 141 173 197

89 89 89 89 89

x x x x x

89 140 184 235 286

92.0 125 152 178 197

96.3 125 153 175

89 89 89 89 89

x x x x x

89 140 184 235 286

66.3 90.4 110 128 142

69.4 90.3 111 126

4" SH

~

2-1/2" SR

172 200

125 160 194 220

158 183

114 146 178 201

140 162

101 130 158 178

101 117

72.9 93.5 114 129

TrN for use with shear plates or split rings (kN)

4" SR

Tr kN

2-5/8" SH ~

175 203

62.0 84.6 103 120 133

65.0 84 104 118

160 185

66.3 90.4 110 128 142

69.4 90.3 111 126

142 164

58.8 80.2 97.3 114 126

61 .6 80.1 98.2 112

103 119

42.8 58.3 70.7 82.8 91 .6

44.8 58.3 71.4 81 .2

4" SH

2-1/2" SR

4" SR

94.3 109

68.2 87.5 106 120

95.9 111

101 117

72.9 93.5 114 129

103 119

89.4 104

64.7 83.0 101 114

91.0 105

65.0 75.4

47.0 60.3 73.3 83.0

66.1 76.5

~

Notes : 1. Tr = Factored tensile resistance based on gross area TrN = Factored tensile resistance based on net area with a single shear plate or split ring on each side of member at a given cross section :

8 2. SH ~ = Shear Plate, SR = Split Ring 3. Where Tr values are not shown, area removed exceeds 25% of gross area. 4 For 4" diameter shear plates, values are based on the use of 3/4" diameter bolts.

Wood Design Manual

Tension Member Selection Tables Sawn Timber Select Structural

No.1

T'N for use with shear plates or split rings (kN)

Species D.Fir-L

Hem-Fir

S-P-F

Northern

Size (b x d) T, mm kN

2-5/8" SH It 1 row 2 rows

4" SH It 1 row 2 rows

140 140 140 140 140 140

x 241 x 292 x 343 x 394

245 309 334 368 389 397

196 264 295 332 357 369

256 297 325 340

245 279 318 344 357

140 140 140 140 140 140

x 140 x 191 x 241 x 292 x 343 x 394

181 228 247 272 288 294

145 195 218 246 264 273

189 220 241 252

181 207 235 255 264

140 x 140 140 x 191 140 x 241

170 214 234

136 182 207

140 x 140 140 x 191 140 x 241

161 202 217

128 172 192

x 140 x 191

T,N for use with shear plates or split rings (kN)

kN

2-5/8" SH It 1 row 2 rows

4" SH It 1 row 2 rows

299 317

186 234 234 258 272 278

148 199 207 233 250 258

179 208 228 238

185 195 223 241 250

209 222

221 235

138 173 174 191 202 207

110 148 153 173 186 192

133 154 169 177

137 145 165 179 186

156 165

179

169 195

128 162 164

103 138 145

125

128 137

166

160 181

122 153 154

97.1 131 136

118

121 128

T,

Notes: 1. T, = Factored tensile resistance based on gross area T,N = Factored tensile resistance based on net area with one or two single shear plates or split rings on each side of member at a given cross section

8 8 One row

Two rows

2. SH It = Shear Plate, SR = Split Ring 3. Where T, values are not shown, area removed exceeds 25% of gross area. 4 For 4" diameter shear plates, values are based on the use of 3/4" diameter bolts.

4

166

Tension Members

Tension Member Selection Tables Sawn Timber Select Structural

Species D.Fir-L

Hem-Fir

S-P-F

Northern

No.1

T'N for use with shear plates

T,N for use with shear plates

or split rings (kN)

or split rings (kN)

Size (b x d) T, mm kN

2-5/8" SH Ie. 1 row 2 rows

4" SH Ie. 1 row 2 rows

T,

kN

2-5/8" SH Ie. 1 row 2 rows

4" SH Ie. 1 row 2 rows

191 191 191 191 191

x x x x x

191 241 292 343 394

422 488 502 531 542

364 435 457 490 506

382 412 450 470

345 418 443 477 494

383 424 447

319 369 351 371 379

276 329 320 343 354

289 289 315 329

261 316 310 334 346

268 297 313

191 191 191 191 191

x 191 x 241 x 292 x 343 x 394

311 360 371 393 401

269 321 338 363 374

282 305 333 348

255 308 327 353 366

284 314 331

236 273 261 276 282

204 244 238 255 263

214 214 234 244

194 234 230 248 257

199 220 232

191 x 191 191 x 241

292 337

252 301

264

239 289

221 255

190 227

200

181 219

191x191 191 x 241

276 319

238 284

250

226 273

209 242

180 215

189

171 207

Notes:

1. T, = Factored tensile resistance based on gross area T'N

=Factored tensile resistance based on net area with one or two single shear plates or split rings on each side of member at a given cross section

0) 0) One row

Two rows

2. SH Ie. = Shear Plate, SR = Split Ring 3. Where T, values are not shown, area removed exceeds 25% of gross area. 4 For 4" diameter shear plates, values are based on the use of 3/4" diameter bolts.

Wood Design Manual

167

Tension Member Selection Tables Sawn Timber Select Structural

No.1

T'N for use with shear plates or split rings (kN)

2 rows

T, kN

2-5/8" SH ~ 1 row 2 rows

4" SH 1 row

534 604 608 629

531 546 574

466 513 469 479

417 469 435 448

369 425 400 418

405 457 425 440

402 382 402

360 415 423 442

395 446 450 465

392 404 425

345 380 348 356

309 348 323 333

274 315 297 310

300 339 316 327

298 284 298

382

337

370

322

288

256

280

361

319

350

305

273

242

265

Size (b x d) T, mm kN

2-5/8" SH ~ 1 row 2 rows

4" SH 1 row

241 241 241 241

x 241 x 292 x 343 x 394

615 678 670 684

552 620 621 640

488 562 572 597

241 241 241 241

x 241 x 292 x 343 x 394

454 500 495 506

407 458 459 474

S-P-F

241 x 241

426

Northern

241 x 241

403

Species D.Fir-L

Hem-Fir

~

T'N for use with shear plates or split rings (kN) ~

Notes : 1. T, = Factored tensile resistance based on gross area T,N = Factored tensile resistance based on net area with one or two single shear plates or split rings on each side of member at a given cross section

8 8 One row

Two rows

2. SH ~ = Shear Plate, SR = Split Ring 3. Where T, values are not shown, area removed exceeds 25% of gross area. 4 For 4" diameter shear plates, values are based on the use of 3/4" diameter bolts.

2 rows

4

168

Tension Members

Tension Member Selection Tables Glulam 18t-E D.Fir-L

14t-E Spruce-Pine

Factored tensile resistance based on gross area

Factored tensi le resistance based on gross area

Size (b x d) mm 80 80 80 80 80

x 152 x 190 x 228 x 266 x 304

Maximum number of shear plates per side for TrN ~ T rG 2-5/8"

4"

196 245 294 343 392

Maximum number of shear plates per side for TrN ~ T rG

2-5/8" 147 183 220 257 293

1 1 1 1 2

238 298 357 417 477

1 1 1

2 2

1 2 2 2 2

536 596 655 715 774

2 3 3 3 4

2 2 2 2 3

1

1

2 2 2 3

1 1 1 2

x 152 190 x 228 x 266 x 304

318 398 478 557 637

1 1 1 2

x 342

2 2

x 456 x 494

716 796 875 955 1030

190 x 228 x 266 x 304 x 342

536 643 750 857 964

2 2 2

2

401 481 561 642 722

x 380

3 3 3 4

2 2 2 3

802 882 962 1040

3 3

x 456 x 494

1070 1180 1290 1390

215 x 266 215x304 215 x 342 215 x 380 215 x 418 215 x 456 215x494

921 1050 1180 1320 1450 1580 1710

2 2 2 3 3 3

1 2 2 2 2 3 3

690 788 887 985 1080 1180 1280

2 2 3 3

130 130 130 130 130 130 130 130 130 130 175 175 175 175 175 175 175 175 175

x

x 380

x 418

x

x 418

2

3 3 3 1 1

4

1 1 1

4 4

4 4

4

Notes: 1. Number of shear plates per side at a given cross section :

0) 0) One per side

4"

Two per side

2. For 4" diameter shear plates, values are based on the use of 3/4" diameter bolts.

2 2 2 3 3

2 2 2 2 3 3 3

Wood Design Manual

169

Tension Member Selection Tables Glulam 2Of-EX and 24f-EX D.Fir-L

20f-EX Spruce-Pine

Factored tensile resistance based on gross area

Factored tensile resistance based on gross area

Maximum number of shear plates per side for T rN 2: T rG

TrG kN

2-5/8"

Size (b x d) mm 80 80 80 80 80

152 190 228 266 x 304

Maximum number of shear plates per side for TrN 2: T rG

2-5/8"

4"

4"

1 1 1 1

167 209 251 293 335

1 1 1 1 2

139 174 208 243 278

272 340 408 476 544

1 1 1

2 2

226 282 339 395 452

x 456 x 494

612 680 748 816 880

2 3 3 3 4

2 2 2 2 3

508 565 621 678 734

175 175 175 175 175

x 190 x 228 x 266 x 304 x 342

458 549 641 733 824

1

2 2 2 3

1 1 1

2 2

380 456 532 608 684

175 175 175 175

x 380 x 418 x 456 x 494

920 1010 1100 1190

3 3 4

2 2 3 3

760 836 912 990

3 3 4 4

2 2 3 3

266 304 342 380 x 418 x 456 x 494

788 900 1010 1130 1240 1350 1460

2 2 3 3 4 4 4

2 2 2 2 3 3

654 747 840 934 1030 1120 1210

2 2 3 3 4 4 4

2 2 2 2 3 3 3

x x x x

130 130 130 130 130 130 130 130 130 130

215 215 215 215 215 215 215

x 152

x x x x

190 228 266 304

x 342 x 380

x 418

x x x x

4

3

2 1 1

2 2 2 3 3 3 4 4 1

2 2 2 3

Notes: 1. Number of shear plates per side at a given cross section :

8 8 One per side

Two per side

2. For 4" diameter shear plates, values are based on the use of 3/4" diameter bolts.

2 2 2 2 3 1 1 1

2 2

170

Tension Members

Combined Loads

5.1 General Information .. ... ... ..... ..... 175 5.2 Stud Walls ... . . . .... . .. .. .......... 191

5

172

Combined Loads

Wood Design Manual

The top chords and often the bottom chords of trusses are subjected to combined bending and axial stresses.

173

174

The high stud walls used in applications such as this church require that the designer consider deflection limitations as well as combined bending and axial stresses.

Combined Loads

Wood Design Man ual

5.1

175

General Information This chapter contains design information for members that are subjected to combined bending and axial load . Combined bending and axial compression often occurs in glulam arches and the top chords of trusses, as well as in laterally loaded studs and columns. Members loaded in bending combined with tension are less common, and include the bottom chords of trusses or top chords of trusses subject to uplift loading. Permanent wood foundations are also subjected to combined loading , and design information is provided in Section 8.8. Generally, the 2Of-EX or 24f-EX stress grades are used for glulam subjected to combined loads ; however, 18t-E, 14t-E, 16c-E or 12c-E grades may be used. This section provides design information for the 2Of-EX and 24f-EX grades only.

5

Design Members subjected to combined bending and axial compressive or tensile loads must be designed to satisfy the appropriate strength interaction equation . With the exception of stud walls for permanent wood foundations and specific truss configurations, the following interaction equations are applicable :

(")

o 3

tT

s·

~

S Q)

Pf + Mf s 1.0 Pr Mr

where : Pf

= factored axial compressive load

Tf

= factored axial tensile load = factored bending moment, taking into account end moments and

Mf

amplified moments due to axial loads in laterally loaded members (see below) Pr

= factored compressive resistance parallel to grain

Tr

= factored tensile resistance parallel to grain = factored bending moment resistance

Mr

The interaction equation applicable to the design of stud walls for permanent wood foundations is given in Section 8.8 of this manual. Refer to clause 5.5.13 of CSA 086 for the interaction equation applicable to specific truss applications. When checking the interaction equation for bending and compression , the compressive resistance Pr is calculated as if only compressive loads were present. Therefore , it is always based on buckling in the weakest direction. The factored resistances Pr, Tr and Mr may be found in the appropriate sections of this manual as indicated in Table 5.1 . In addition , selection tables for stud walls subjected to combined lateral wind loading and axial loading are provided in Section 5.2.

Q.

III

176

Combined Loads

Table 5.1 Factored resistances for combined bending and axial load

Material

P,

T,

M,

Sawn Lumber

Section 3.2

Tension Member Selection Tables, Section 4.2

Joist Selection Tables, Section 2.3

Sawn Timber

Section 3.3

Tension Member Selection Tables, Section 4.2

Beam Selection Tables, Section 2.4

2Of-EX, 24f-EX Glulam

Section 5.1

Tension Member Selection Tables, Section 4.2

Beam Selection Tables, Section 2.4

Bending Moments in Laterally Loaded Compression Members When a compression member is laterally loaded, a secondary bending moment is created by the product of the axial load and the total lateral deflection (P~ effect). The total moment is then calculated as follows: Mf

= M't + Pf ~T

where: M'f

= factored

Pt

= factored axial load = total lateral deflection

~T

bending moment due to lateral loading only

The total lateral deflection ~T consists of the deflection due to the lateral loading ~L plus additional deflections caused by the secondary moment. This may be calculated by multiplying ~L by an amplification factor as follows:

where: Pf PE

= factored axial compressive load = Euler buckling load in direction of applied moment =

Jt2

Esl

(Ke

L)2

Esl

= bending stiffness, given in Joist and Beam Selection Tables

Ke

= effective length factor, given in Figure 3.1 = unsupported length in the direction of the applied bending moment

L

Wood Design Manual

177

As an alternative, the total bending moment for simply supported members may be estimated with reasonable accuracy by amplifying the bending moment due to lateral loading as follows:

For other support conditions, this expression may slightly underestimate the total moment.

Bending Moments in Eccentrically Loaded Compression Members When a load is not applied in the center of the vertical axis of a compression member, the eccentricity will create a moment. At the location where the load is applied (typically the top of the column) there is no deflection and the moment is calculated as: MI where: MI PI e

= PIe

a.

UI

= factored bending moment due to eccentricity = factored axial load

= load eccentricity = distance between the center of the column and the

MI = Mil + PI ~E where:

= factored bending moment due to eccentricity at the mid point =

between the applied load and the column base 1 - Pe 2 I

= total lateral deflection at mid height due to the eccentric load

The total bending moment at the mid point on the compression member may be estimated as : MI

~

g

Midway between the location where the load is applied (typically mid-height of the column) and the column support the total moment is calculated as:

~E

3

C" s·

r

centroid of the applied load

Mil

oo

=

1 - Ple - -

2

1_iL

PE

178

Combined Loads

Lateral Restraint

In the calculation of moment resistance for combined bending and compression, the lateral stability factor KL may be taken as unity where lateral support is provided at points of bearing and the depth to width ratio of the member does not exceed the following values: 4:1 5:1 6.5:1

if no additional intermediate support is provided if the member is held in line by purlins or tie rods if the compressive edge is held in line by direct connection of decking or joists spaced not more than 610 mm apart if the compressive edge is held in line by direct connection of decking or joists spaced not more than 610 mm apart and adequate bridging or blocking is installed at intervals not exceeding 8 times the depth of the member if both edges are held in line

7.5:1

9:1

These rules apply to glulam members as well as sawn lumber and timber. If the above limits are exceeded , KL may be calculated in accordance with CSA 086 Clause 6.5.6.4. Example 1: Glulam Column

Design the glulam column shown below. Use untreated 2Of-EX Spruce-Pine glulam in dry service conditions. The axial load consists of 10 kN dead load and 40 kN snow load. The specified wind load is 10 kN for strength calculations and 7.5 for serviceability calculations. The specified wind loads are based on the q1 /50 hourly wind pressure, wind importance factors , internal and external pressure coefficients and the tributary wind load area. Calculation Load Case 1: (1 .250 + 1.5S)

PI

= (1 .25 x 10) + (1.5 x 40) = 72.5 kN P = 50 kN

2.5 m

Restrained in weak di rection

2.5 m

P = 50 kN

179

Wood Design Manual

Load Case 2: (1 .250 + 1.4W + 0.5S) PI

= (1 .25 x

10) + (0.5

x

40)

= 32.5 kN

WI = 1.4 x 10 = 14 kN Load Case 3: (1.250 + 1.5S + O.4W) PI

= (1 .25 x 10) + (1.5 x 40) = 72.5 kN

WI = 0.4 x 10 = 4 kN 1. For Load Case 1 (standard term load) Select initial trial section 130 x 152 mm: Cex

=

Ke Ld d

1.0 x 5000 152

=

32.9

Cey

=

Ke Lb b

1.0 x 2500 130

=

19.2

Governs

Since buckling about X axis governs, Column Selection Tables may be used because Ke Ld = L. Therefore, from Column Selection Tables: Pr = Prx = 101 kN > 72.5 kN

Acceptable

The 130 x 152 mm section is adequate for Load Case 1. 2. Check 130 x 152 mm section for Load Case 2 (short term load) a) Calculate Pr For short term loads Column Selection Tables cannot be used. Pr = Feb

Feb A KZe Kc = 23.2 MPa from Table 5.2

= 130 x 152 = 19760 mm 2 Kze = 0.68 (0.130 x 0.152 x 5.0)-0.13 =0.92

A

Kc =

[1.0+

~~ KZe C~

r

Cex = 32.9 Feb / E' = 92.4 x 10-6 from Table 5.3 Kc Pr

= [1.0 + 92.4 x 10-6 x 0.92 x (32.9)3]-1 = 0.25 = 23.2 x 19760 x 0.92 x 0.25 = 105 kN

Governs

180

Combined Loads

b) Determine Mr using Beam Selection Tables: A review of the checklist for beams indicates that the tabulated M'r values may be multiplied by 1.15 for short term loading. (note that KL = KZb9 = 1)

Mr Mf

= 1.15 x 11.5 = 13.2 kNom = WI L _ 14.0 x 5.0 4

-

4

= 17.5 kNom > 13.2 kNom

Not Acceptable

c) Select a larger section: Try 130 x 228 mm section Ccx = 1.0 x 5000/228 = 21.9

Governs

A = 130 x 228 = 29640 mm 2 Kzc = 0.68 (0.13 x 0.228 x 5.0)-0.13 = 0.87 Kc = [1 + 92.4 x 10-6 X 0.87 x (21.9)3]-1 = 0.54

P r = 23.2 x 29640 x 0.87 x 0.54 = 323 kN Mr = 1.15 x 26.0 = 29.9 kNom Note that since d 1 b < 4, the factor KL may be taken as unity. According to Table 2.11 , KZbg = 1.0. d) Calculate amplified bending moment and verify interaction equation : Esl = 1320 x 109 Nomm 2

09

2

:rr: x 1320 x 1

=

521 kN

(5000)2

p]-l [ 1 where: 1 - ~

Mf

=

14.0 x 5.0 4 x 1.07

!l + ~ Pr

Mr

=

[325]-1 ) 1- 5~1 = 1.07

= 18.7kNom

32.5 18.7 + - - = 0.73 323 29.9

= --

Acceptable

e) Check shear

Vf = 14/2 = 7.0 kN beam volume = 0.130 x 0.228 x 5.00 = 0.148 m3 < 2.0 m3 Check Vr from the Beam Selection Tables. A review of the checklist indicates that Vr values may be multiplied by 1.15 for short term loading.

Vr = 1.15 x 31 .1 = 35.6 kN > 7.0 kN

Acceptable

Wood Design Manual

181

Checklist: Glulam Columns

(Combined Loading)

"

To verify that the tabulated resistances given in the Column Selection Tables are appropriate for the structure being designed, the following questions should be asked: 1. Is load duration "standard" term (dead load plus snow or occupancy loads)? 2. Is the service condition "dry"? 3. Is the material free of strength reducing chemicals such as fire retardants? 4. Is the effective length factor Ke equal to 1.0 and the effective column length in the direction of buckling equal to the total column length? C)

If the answer to any of these questions is no, the Column Selection Tables may not be used. Instead, calculate Pr as shown in Example 1: Glulam Column.

o 3

tT

il) .,

Q.

f) Check U180 deflection limit based on serviceability wind load

E s IREQ'D

= 180

W 1/50 [

48

L2] =

180

[7500

x 5000

In

2]

48

=703 x 109 N ·mm2 < 1320 x 109 N 'mm 2

Acceptable

3. Check 130 x 228 mm for Load Case 3 (short term load)

M ,= W 4L[l-H' {Where [l-H' = [1- ~~~r = 116} 4 x 5.0 4 x 1.16 = 5.80 kN· m

P. --1.

Pr

M,

+ --'Mr

72.5 5.80 =- + - - = 0.42 323

29.9

Use 130 x 228 mm 2Of-EX Spruce-Pine glulam.

Acceptable

182

Combined Loads

Example 2: Eccentrically Loaded Glulam Column Design a glulam column supporting a glulam roof beam. The roof beam is supported on a bracket attached to the narrow face of the column. The width of both the beam and the column is 130 mm. The distance between the edge of the column and the center of the bracket is 60 mm and the distance between the underside of the bracket and the base of the column is 4 m. Use untreated 2Of-EX D.Fir-L glulam in dry service conditions. The axial load consists of 10 kN dead load and 40 kN snow load. Calculation Load Case: Dead plus snow:

P,

= (1.25 x 10) +

(1.5 x 40)

= 72.5 kN

Select trial section 130 x 190 mm: a) From Column Selection Tables (combined loading) , check axial capacity in the Y axis: Pry

= 175 kN > 72.5 kN

Acceptable

b) Check combined axial and moment resistance in the X axis at the top of the column. Since there is no deflection at the top of the column moment amplification is not considered: Calculate eccentricity, e: e

= 190/2 + 60 = 155 mm

M = 72.5 x 155 = 11.2 kN om , 1000 From Beam Selection Tables:

Mr

= 18.0 kNom

From Column Selection Tables (combined loading): Prx

P,

= 325 kN M,

- +Pr Mr

72.5

11.2

325

18.0

= - - + - - = 0.85

Acceptable

c) Check combined axial and moment resistance in the X axis at the mid-height of the column : Calculate the amplified bending moment and verify the interaction equation: Esl = 921 x 109 Nomm 2

1

M,

155

1

="2 Pte - -P-

1-~

2

x 72.5 x

PE

P, M, - + Pr Mr

72.5

6.44

325

18.0

1000

72.5 1- 568

= - - + - - = 0.58

Use 130 x 190 mm 2Of-EX D.Fir-L glulam.

= 6.44 kNom

Acceptable

183

Wood Design Manual

Table 5.2 Factored compressive strength for glulam subjected to combined bending and axial compression ~ Feb (MPa)

Table 5.3 Modified strength to stiffness ratio for glulam Feb I E' (x10-6)

Dry service

Wet service Load duration

Load duration Grade

Std.

Perm.

Short term

D.Fir-L 24f-EX and D.Fir-L 2Of-EX

24.2

15.7

27.8

18.1

11 .8

20.8

Spruce-Pine 2Of-EX

20.2

13.1

23 .2

15.1

9.83

17.4

Std .

Perm.

Short term

Notes: 1.