bundled tube
A system in which multiple tube structures are clustered together for greater strength.
Pictured: Willis Tower
A bundled tube system employs more than one framed or trussed tube, clustered together to resist lateral forces. This adds strength to a structure, in the same manner that a bundle of straws is harder to bend than a single straw.
The constituent tubes are grouped so that their resistance to lateral forces works together. A framed tube, a trussed tube, or more than one of either form can supply the individual tube elements.
The arrangement differs from a tube-in-tube system, which places an inner tube at the core and an outer tube at the perimeter. Merely having several nearby towers does not establish a structural bundle.
