Chapter 4: Heavy Timber Frame Construction Flashcards
Explain why heavy timber may be used in building construction (in relation to fire).
It is slower to catch fire and burn than smaller pieces of wood. The charred out layer of a partially burned timber insulates and protects the inner portion, preserving partial structural capacity.
When reading a fire-resistance chart, what is the difference between A and B in different building types?
A is likely more fire-resistant than B.
What do you classify wood members with a lesser dimension than is required for Heavy Timber?
Wood Light Frame (Type V) Construction
Read this information about shrinkage.
Differential rates between interior wood framing and exterior noncombustible walls leads to differential setting of upper floors and roofs.
Wood connection details should minimize cumulative effects of cross-grain shrinkage.
When would you use Heavy Timber (Type IV)? Describe this use.
Floor and roof decks: heavy decking comes in depths of 2-8”. It is capable of spanning roughly from 5’-20’. To achieve required fire-resistance, the decking must be covered with tongue-and-groove boards or plywood. Concealed combustible spaces (where a fire could develop undetected) must be avoided.
True or false: when used with other construction types, heavy timber is not subject to others’ height and area requirements.
False; it is subject to this type’s height and area.
Describe heavy timber in roof framing.
It is permitted in any construction type requiring no more than a 1-hour fire-resistance rating. For example, a heavy timber framing can substitute 1-hour protected steel or concrete roof framing in Type I and II noncombustible buildings.
What are different types of lateral bracing?
Knee bracing
Full bay cross bracing
Shear walls
Structural wood panels
Stiffens the column or beam connection and adds lateral stiffness to the heavy timber frame.
Knee bracing
Masonry or concrete walls that provide lateral stability
Shear walls
Panels attached to the frame that act as shear walls
Structural wood panels
What are two types of cross-laminated timber construction?
Cross-laminated timber: each layer of boards is perpendicular to adjacent layers and glued on the wide faces of each board.
Glue-laminated timber: a product with all laminations oriented in the same way.
_____ _____ are shipped to the construction site and lifted into place. They can act as loadbearing walls, floors, and roof decks.
Fabricated panels
How do you solve this: If a 5/8” oriented strand board sheathing is nailed to the wood frame of a building with 8d (2-1/2”) common nails how far does the point of the nail penetrate into the frame?
Use the chart to define the depth of 8d (which is 2-1/2”). Since the sheathing is on top of the wood frame, subtract the depth of the nail by the sheathing (2.5”-0.625) to get 1.875” (or about 1-7/8”).
How would you solve (SHRINKAGE): the total platform frame of a building is 33” cross-grain wood between foundation and roof. Assuming that plainsawn framing lumber shrinks across its grain at a rate that is an average of the shrinkage rates of tangential and radial shrinkage, how much will the roof drop if the lumber is installed at 19% MC and dries t 15%?
Plainsawn means a tangential shrinkage. Review the chart on page 95 for moisture content. At 19%, the tangential shrinkage is about 1.7%. At 15%, the tangential shrinkage is about 2.6%. The difference between these, 9%, is multiplied by 33”. (Keep in mind that 9% is actually 0.09*33.) The answer is 0.297” shrinkage.
