It appears that you called it exactly right, _Jim. It's too bad that on the thread where you explained this you were pooped on by a bunch of anarchist, conspiracy-sniffing loons.
It's too bad that on the thread where you explained this you were pooped on by a bunch of anarchist, conspiracy-sniffing loons.I allow two types of living beings to 'poop' on me on account of *who* they are -- one group is the 1) anarchy-bound, conspiracy-sniffing loons and the other is 2) a member of the Cockatiel (bird) family.
Both groups possess about the same intelligence level, one group, however, *is* working at maximum intellectual capacity ...
I came across this pice while debating this subject with another group:
From:http://lava.ds.arch.tue.nl/lava/people/rob/slany/
TUBULAR SYSTEMS
@@@ A recent development in structural design is the concept of tubular behaviour introduced by Fazlur Khan of S.O.M. At present, four of the world's five tallest buildings are tubular systems. They are the Hancock Building, the Sears Building, and the Standard Oil Building in Chicago, and the World Trade Center in New York.
Tubular systems are so efficient that in most cases the amount of structural material used per square foot of floor space is comparable to that used in conventionally framed buildings half the size.
Tubular design assumes that the facade structure responds to lateral loads as a closed hollow box beam cantilevering out of the ground. Since the exterior walls resist all or most of the wind load, costly interior diagonal bracing or shear walls are eliminated.
The tube's walls consist of closely spaced columns around the perimeter of the building tied together by deep spandrel beams. This facade structure looks like a perforated wall. The stiffness of the facade wall may be further increased by adding diagonal braces, causing trusslike action. The rigidity of the tube is so high that it responds to lateral loading similar to a cantilever beam.
As we see later, the exterior tube alone can resist all lateral loads entirely, or it can be further stiffened by adding interior bracing of some kind. The earliest application of the tubular concept, was first used in the 43-story Dewitt Chestnut Apartment Building in Chicago (S.O.M., 1961).
In this Vierendeel tube system the exterior walls of the building, consisting of a closely spaced rectangular grid of beams and columns rigidly connected together, resist lateral loads through cantilever tube action without using interior bracing.
The interior columns are assumed to carry gravity loads only and do not contribute to the exterior tube's stiffness. The stiff floors act as diaphragms with respect to distributing the lateral forces to the perimeter walls.
Other examples of hollow framed tube buildings are the 83-story Standard Oil Building in Chicago and the 110-story World Trade Center in New York.
Although these buildings have interior cores, they act as hollow tubes because the cores are not designed to resist lateral loads.