framed tube
A system which resists lateral forces through a tightly interlocked perimeter frame.
Pictured: The Plaza on Dewitt
A framed tube structure resists lateral forces with a strong, tightly connected perimeter framework, requiring closely spaced columns at the edge of the structure. This allows for large open spaces within the building plan, even in a very tall structure.
Closely spaced perimeter columns and their tight connections make the outside framework act together against lateral forces. The structural tube is formed by that perimeter frame.
The arrangement can leave large interior spaces open without making a completely column-free interior mandatory. A loose perimeter grid without the strong connecting action does not provide the same framed-tube system.
