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 Copyright © 2009 J. Iano. All rights reserved.

HISTORY Contemporary Contemporary timber frame construction may be used for both residential and nonresidential structures. Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 J. Iano. All rights reserved.

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

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 Copyright © 2009 J. Iano. All rights reserved.

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. Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 J. Iano. All rights reserved.

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 Copyright © 2009 J. Iano. All rights reserved.

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 Copyright © 2009 J. Iano. All rights reserved.

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.

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 Copyright © 2009 J. Iano. All rights reserved.

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 Copyright © 2009 J. Iano. All rights reserved.

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.

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 Copyright © 2009 J. Iano. All rights reserved.

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.

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.

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 Copyright © 2009 J. Iano. All rights reserved.

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.

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.

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.

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.

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.

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

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.

CONNECTIONS Proprietary fastening system with self-drilling steel dowels and concealed steel plates Fundamentals of Building Construction, Materials & Methods, 5th Edition Copyright © 2009 J. Iano. All rights reserved.

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 Copyright © 2009 J. Iano. All rights reserved.

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 Copyright © 2009 J. Iano. All rights reserved.

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.

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

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.

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.

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.