Transcript Heavy Timber - Morrison Institute of Technology

Heavy Timber
Materials and Methods
What is Heavy Timber
• Type 4 Construction
• Heavy timber also referred to as Mill
construction or slow burning construction
• Minimum sizes for timbers and decking of
heavy timber construction are specified in
another section of the code, these
requirement are summarized to the right.
Why use Heavy Timber
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Fire Resistance
Large timbers absorb a lot of heat
Slower to catch fire and burn
Will continue to support loads long after
unprotected steel beams would.
Heavy Timber Shrinkage
• Because of size shrinkage is a major factor
Cross grain wood is eliminated
• Today we use more laminated wood to
eliminate shrinkage
Anchoring Beams to Masonry Walls
• Space kept between bean and wall to
eliminate moisture
• Cut at angle in case
Floor and roof decks for heavy timber
• Code requires that heavy timber buildings
have floors and roofs of solid wood
construction without internal cavities
• These poses problems with mechanical
systems
Combustible Buildings framed with
heavy timber
• Heavy timbers are often used in combination
with smaller wood framing members to construct
buildings that do not meet all the fire-resistive
requirements for heavy timber construction.
These buildings are classified as type 5
• This type of construction brings the appearance
and structural performance of beam and decking
framing to small freestanding buildings
Heavy Timber Spans
• Are typically less than 20ft unless laminated
Heavy Timber Arcs
• Originally cut from bent trees
• Today laminated to shape
Heavy Timber Trusses
• Span distances of over 100ft
• Rather then toothed plates joints are made
with steel bolts and welded steel plates
connections.