Posted by Paul Malo on September 19, 2002 at 10:13:20:
In Reply to: Re: Future High Rise Design: More Concrete posted by d on September 19, 2002 at 09:37:08:
No diagonals? You forget that all the WTC floors were trusses, which employed diagonals. Furthermore, most highrise structures utilize a concrete core which has shear walls that provide diagonal bracing. Without the diagonal resistance, buildings are houses of cards. The exception is use of the rigid frame, where joints are strengthed to resist diagonal deformation. Because of cost, this method generally is restricted to small structures.
There's nothing innovative about the diagonal, which we employ regularly in pitched roofs as simple trusses, and in other trusses used for roof and (as at the WTC) floor systems. The Eiffel Tower was not innovative structurally--it was simply big. Engineers have understood the principle of the truss for a long time--and the diagonal as inuitive bracing is even older.. Indeed, you mention the Medieval half-timber house with its "expressive" diagonal bracing.
The problem with the "oblique" forms is not structural but practical. How do you put furniture against an inclined wall--or into a corner that's not a right angle? Conventions may seem tiresome to some, but they're conventional for a reason.
Fuller's Dymaxion House was a case study. It was ingenious, but useless.
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