Conversation so far:
What was the tube structural system?
The exterior wall perimeter of a building simulates a thin-walled tube to resist lateral loads such as wind forces and seismic forces.
Did tube structural system do well?
Fazlur Rahman Khan's tube concept revolutionized tall building design. Most buildings over 40 stories constructed since the 1960s now use a tube design derived from Khan's structural engineering principles.

Question: Was this system used for anything else?
Self-contained rewrite: Was the tube structural system used for anything else besides buildings?