Dave Hinz wrote:

On Sun, 12 Aug 2007 08:14:44 +1200, Tom wrote:


I notice that there is a fast growing
prevalence in the US for people to employ drivers to get them across bridges,
your doing?


Where in the world did you imagine _that_ is true, Tom?

Perhaps you need to watch some current domestic news, Dave?
A news story on this from the US was screened down here yesterday.


As for the 2000 year bridges, they did what they were designed to do
with a safety redundancy that sees them still standing. I think there's
been odd American, John A Roebling springs to mind, who have been able
to do this.


It depends on what your priorities are, doesn't it? A 100 year design
life for a car, would be silly. 10 years is about right, and a good
balance between cost, weight, and the realities of how a car is used.
Similar for a bridge - a 100 year design life is reasonable. 1000 year?
Why should I pay so much more for a bridge today? Does the
overengineering that would take make it any better to use, or does it
just make it last longer?

LOL Or should I be cringing over your rationale? Hopefully you have
never been involved with anything structural, nor especially the
aircraft industry.

BTW The bridge in question didn't meet you expectations by quite a large
margin. How many more are out there of similar age and design?
I think there's a growing number of Americans, who are every day, crossing
bridges with considerable trepidation.

Tom