On 6/27/2010 08:16, Graham Harrison wrote:

"Basil Jet" wrote in message
...
On 27/06/2010 12:15, Graham Harrison wrote:

"E27002" wrote in message
...
On Jun 26, 8:15 am, Basil Jet wrote:
Why are American cities full of open girdered viaducts whereas British
cities are full of brick viaducts?

Availability of materials.

================

Might it also be something to do with the very nature of the viaducts?
If you think about the "elevateds" in the US many of them were built
over roads and I'm not sure how practical it would have been to use
brick for that.

I think you've put the cart before the horse. It's not that London
viaducts utilise brick because they are not over roads - they don't have
roads beneath them because they utilise brick.

Take your point but I'm still not sure that the "Els" would have been built
in brick.

And I think that has the seeds for the answer.

"Viaducts" are often designed by engineers, who used to consider cost,
availability of materials, nature of problem, tectonics, geology, and
more that don't come to mind.

Lots of places have what amount to viaducts made of huge, long piles of
dirt (railroads, highways), naked steel (railroads, els [to minimize
airspace used]), reinforced concrete, concrete encased steel, bricks,
stone. At Center near Industrial it looks like they are widening the
railbed using steel-reinforced dirt.


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Freedom under a constitutional republic is a well armed lamb contesting
the vote.

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