Volkswagen--
We Thank You
And
why are there no old roofs?
by
David B. South, Jr.
reprinted from The Monolithic Dome Roundup Summer 2001
The other night while relaxing and watching TV, I was quite surprised when a commercial came on extolling the virtues of dome construction. It's not every day that a man, who appears to be a professor, stands in front of a dome explaining in plain language the advantages of the dome structure.
Then a new Volkswagen Beetle drove up in front of the dome and a large car load of people got out. All the while, the professor explains that domes enclose the "most volume in a minimum space."
I think the best line was his closing one, "With such an efficient design, it's a wonder domes aren't seen more often today." Obviously Volkswagen's intent was to sell more cars. But I'm positive that the primary benefit of this commercial is educating the public about the advantages and strengths of the dome - with a side benefit of selling a few more cars.
So
to Volkswagen, we thank you!
It's The Roof That Matters
Building
a wall is easy. Nearly any material - earth, wood, straw, car tires -
can make a reasonable wall. Walls can encircle nearly any area, even whole
cities.
But when you try to put a roof on top of the wall, that's where things
get difficult. Gravity creates a remarkable lever action between the roof
structure and the walls and even between the roof's own structural elements.
Even
the modest span of a house requires trusses and interior bearing walls.
Just imagine the difficulties of spanning a basketball court or a football
stadium.
During a disaster, the roof is the point of failure for nearly all buildings. And without careful maintenance, all roofs will likely fail through the normal events of time.
Then there is the dome - a symmetrically balanced shape where gravity actually helps by compressing the dome and thereby holding it up while trying to pull it down.
The strength and longevity of the dome is illustrated by the Pantheon in Rome. The Pantheon is nearly two thousand years old. Not only is it still standing with the dome intact, it's still in full use and visited by thousands of people every year.
We cannot find any significant structure of that age with even a moderate span where the roofs did not collapse. Yet the Pantheon, which suffered much abuse during its lifetime, will likely stand for another two millennia.
Of course, there are lots of old walls around, if you are interested.
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