mid_span_framing Flashcards
(20 cards)
What are the two framing systems that revolutionized U.S. housing construction?
Balloon framing and platform framing
Why was balloon framing significant in U.S. history?
It allowed for rapid construction of housing to accommodate mass immigration using low-skill labor and readily available wood
What is a key fire risk associated with balloon framing?
It creates vertical cavities that act like chimneys, spreading fire between floors
What construction innovation helped address fire risks in balloon framing?
Firestops—blocks of wood inserted in stud cavities to slow smoke and flame spread
What is the defining characteristic of balloon framing?
Continuous studs running from foundation to roof
What is the defining characteristic of platform framing?
Each floor is built as a platform, and walls are built and raised on top of each platform
What framing method replaced balloon framing and why?
Platform framing; easier to construct with shorter studs, safer due to built-in firestops
What is the historical significance of post and beam construction?
It was the standard before balloon framing, requiring high skill and heavy joinery
How does fire behavior differ between balloon and platform framing?
Platform framing includes natural firestopping between floors; balloon framing does not
What structural layers are typically included in mid-span post-and-beam systems?
Columns, girders, beams, joists, decking
In framing plans, what typically spans the short direction between columns?
Girders
In framing plans, what typically spans the longer direction between girders?
Beams
What is camber in structural engineering?
A pre-curve built into a beam to counteract deflection under load
What span range is efficient for structural steel in mid-span applications?
25 to 35 feet, possibly up to 40–45 feet
What types of buildings use mid-span structural systems?
Commercial offices, schools, low-rise civic buildings
What engineered wood products are used for medium spans?
Glulams, Parallams, LVLs
What was unique about the Monadnock Building in Chicago?
It was built in two phases: one with load-bearing masonry, the other with a steel frame
Why did bearing wall systems become impractical for tall buildings?
Required massive wall thickness at the base, reducing usable space and increasing material costs
What structural shift occurred in phase two of the Monadnock Building?
Switched from bearing walls to steel column and girder framing
What does decking typically span between in a structural system?
Joists or beams, depending on whether joists are present
