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Re: Seismic and snow

[Subject Prev][Subject Next][Thread Prev][Thread Next] No, I think that was one of the Lake Washington floating bridges east of Seattle, much more recently.  Makes one think that floating (and sinking?) bridges are not too good an idea, eh?  But it was a good excuse to build a new, wider bridge.  Bet it cost less than the $6B our new half-a-bridge is costing here in the San Francisco Bay Area.


In a message dated 6/29/05 11:00:09 AM, rgarner(--nospam--at) writes:
I thought it sank because a contractor left some hatches open??

From: Rhkratzse(--nospam--at) [mailto:Rhkratzse(--nospam--at)]
Sent: Tuesday, June 28, 2005 5:58 PM
To: jwatson(--nospam--at); seaint(--nospam--at)
Subject: Re: Seismic and snow

In a message dated 6/28/05 9:52:26 AM, jwatson(--nospam--at) writes:

The odds that *any* snow is present during an earthquake are very long, even when you have high snow loads like this.  I have read at least one statistical study (can't remember a name at the moment though, sorry) which looked at roof snow loads in place during earthquakes.  Your odds of keeping your money in Las Vegas are much better. 

I'm no statistician, but whenever I read about the probability of such and such a load combination happening I think back to the early '70s and how the Hood Canal (Washington) Floating Bridge was sunk by an incredible combination of a low, ebbing tide and winds blowing exactly down a very long and narrow natural "canal" to develop enough fetch to produce high enough waves to swamp the concrete pontoon bridge and sink it.  I doubt the design engineers considered such a long shot (so to speak) in their calculations.

Ralph Hueston Kratz, S.E.
Richmond CA USA