1. 4 HEAVY TIMBER FRAME CONSTRUCTION
History
Simple timber-framed structures appear with the oldest known civilizations.
The traditional braced frame structure first appears in the middle ages.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
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2. HISTORY
Contemporary
Contemporary timber frame construction may be used for both residential and nonresidential structures.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
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3. FIRE-RESISTIVE HEAVY TIMBER CONSTRUCTION
4 HEAVY TIMBER FRAME CONSTRUCTION
FIRE-RESISTIVE HEAVY TIMBER CONSTRUCTION
Fundamentals of Building Construction, Materials & Methods, 5th Edition
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4. Resistance to Fire of Large Timbers
FIRE-RESISTIVE HEAVY TIMBER CONSTRUCTION
Resistance to Fire of Large Timbers
Large wood members have greater resistance to fire than unprotected steel.
Steel, due to its high thermal conductivity, quickly heats up and loses strength during fires.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
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5. Resistance to Fire of Large Timbers
FIRE-RESISTIVE HEAVY TIMBER CONSTRUCTION
Resistance to Fire of Large Timbers
Large timbers are slow to absorb heat, slow to catch fire, and slow to burn.
The charred outer layer of a partially-burned timber insulates and protects the inner undamaged portion of the timber which retains the capacity to carry some load.
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6. Heavy Timber Construction
FIRE-RESISTIVE HEAVY TIMBER CONSTRUCTION
Heavy Timber Construction
Fire-resistive, traditional Mill Construction consists of heavy timber framing within brick masonry exterior walls.
In the contemporary building code, Type IV Heavy Timber construction requires heavy timber framing within noncombustible—masonry, steel, or concrete—exterior walls.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
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7. Heavy Timber Construction
FIRE-RESISTIVE HEAVY TIMBER CONSTRUCTION
Heavy Timber Construction
Timbers must meet minimum size requirements to qualify as Type IV-HT construction in the building code.
Members with lesser dimensions are classified as wood light frame (Type V) construction.
Supporting Floor Loads
Supporting Roof and Ceiling Loads Only
Columns
8 x 8 (184 x 184 mm)
6 x 8 (140 x 184 mm)
Beams and Girders
6 x 10 (140 x 235 mm)
4 x 6 (89 x 140 mm)
Trusses
Decking
3 decking plus 1" finish (64 mm decking plus 19 mm finish)
2" decking, or 1 1/8" plywood (38 mm decking, or 29 mm plywood)
Fundamentals of Building Construction, Materials & Methods, 5th Edition
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8. Heavy Timber Construction
FIRE-RESISTIVE HEAVY TIMBER CONSTRUCTION
Heavy Timber Construction
In IBC, note how allowable heights and areas of Heavy Timber (Type IV-HT) buildings exceed those for unprotected steel (Type III-B).
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.

9. Heavy Timber Construction
FIRE-RESISTIVE HEAVY TIMBER CONSTRUCTION
Heavy Timber Construction
Allowable heights and areas of Heavy Timber buildings also exceed those of light wood frame (Type V) structures.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
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10. FIRE-RESISTIVE HEAVY TIMBER CONSTRUCTION
Wood Shrinkage
Wood column/beam connections are designed to minimize the effects of cross-grain shrinkage that can lead to differential settling between interior framing and exterior walls made of materials that are not prone to shrinkage.
Right: Traditional cast iron pintle column base.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
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11. FIRE-RESISTIVE HEAVY TIMBER CONSTRUCTION
Wood Shrinkage
Right: Contemporary beam/column connection with bearing blocks, split rings, steel straps.
Note how beam ends are not supported on cross-grain material.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.

12. FIRE-RESISTIVE HEAVY TIMBER CONSTRUCTION
Beam Anchorage
Fire cut beam ends (right): Collapse of beam must not topple supporting wall.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
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13. FIRE-RESISTIVE HEAVY TIMBER CONSTRUCTION
Beam Anchorage
A ventilating air space around the beam end prevents moisture in the masonry wall from seeping into the beam.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.

14. FIRE-RESISTIVE HEAVY TIMBER CONSTRUCTION
Beam Anchorage
Upper clip restrains beam from side-to-side movement while allowing rotation due to structural deflection or beam collapse in a fire.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.

15. FIRE-RESISTIVE HEAVY TIMBER CONSTRUCTION
Floor and Roof Decks
Decking comes in depths of 2" to 8", capable of spanning roughly from 5' to more than 20'.
To achieve the required fire-resistance, floor decking must be covered with tongue-and-groove boards or plywood.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
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16. HEAVY TIMBER CONSTRUCTION
Floor and Roof Decks
Fire-resistive heavy timber floors and roofs must be constructed without concealed cavities where fire could develop undetected.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.

17. Bracing Heavy Timber Structures
LATERAL BRACING
Bracing Heavy Timber Structures
HT structures may be braced against lateral forces with diagonal framing members, shear walls of masonry or concrete, or rigid panels attached to the building frame.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.

18. Bracing Heavy Timber Structures
LATERAL BRACING
Bracing Heavy Timber Structures
To meet contemporary standards, historical structures may require insertion of new steel or reinforced concrete bracing elements.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.

19. Bracing Heavy Timber Structures
LATERAL BRACING
Bracing Heavy Timber Structures
Floor and roof diaphragms must also be securely tied to the supporting structure.
Right: New OSB, metal straps, and structural angles tie the floor structure of an historic mill building to its masonry walls.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.

20. HEAVY TIMBER CONSTRUCTION
Building Services
When floor and roof systems cannot have concealed spaces, services such as lighting, ductwork, sprinkler piping, electrical wiring must be routed in the open.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.

21. CONNECTIONS 4 HEAVY TIMBER FRAME CONSTRUCTION
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.

22. Knee bracing with traditional, pegged mortise and tenon joinery
CONNECTIONS
Knee bracing with traditional, pegged mortise and tenon joinery
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.

23. CONNECTIONS
Proprietary fastening system with self-drilling steel dowels and concealed steel plates
Fundamentals of Building Construction, Materials & Methods, 5th Edition
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24. Fabricated steel seat, concealed plates, and exposed through-bolts
CONNECTIONS
Fabricated steel seat, concealed plates, and exposed through-bolts
Fundamentals of Building Construction, Materials & Methods, 5th Edition
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25. Steel plate gusset with tie rod and through-bolts
CONNECTIONS
Steel plate gusset with tie rod and through-bolts
Fundamentals of Building Construction, Materials & Methods, 5th Edition
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26. CONNECTIONS
Copper sheet metal flashing to protect against moisture absorption at vulnerable ends of large timbers exposed to the weather
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.

27. LONGER SPANS IN HEAVY TIMBER
4 HEAVY TIMBER FRAME CONSTRUCTION
LONGER SPANS IN HEAVY TIMBER
Fundamentals of Building Construction, Materials & Methods, 5th Edition
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28. Large Beams Glulam beams can span over 80', and arches even further.
LONGGER SPANS IN HEAVY TIMBER
Large Beams
Glulam beams can span over 80', and arches even further.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.

29. Trusses Heavy timber trusses can span beyond 200'.
LONGGER SPANS IN HEAVY TIMBER
Trusses
Heavy timber trusses can span beyond 200'.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.

30. Domes The Washington State Tacoma Dome spans 530'.
LONGGER SPANS IN HEAVY TIMBER
Domes
The Washington State Tacoma Dome spans 530'.
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.