To: seaint(--nospam--at)seaint.org, <seaint(--nospam--at)seaint.org>
Subject: RE: What Exposure to use?
From: Neil Moore <nmoore(--nospam--at)innercite.com>
Date: Tue, 12 Jun 2001 22:48:09 -0700
San Francisco Bay gets some big winds! In fact the big winds should be
starting about next month.
We've seen 90 mph winds off of Angel Island. We've been out in the bay in
about 55 mph winds with just a reefed mainsail and a 27,000 lb boat! Not
to many years ago, a big tower went down from about 105 mph winds, if I
remember correctly. I haven't designed anything at Belvedere, but we did
do a number of townhouses in Pacifica where we used exposure D before it
was required by the code. There were storys of the contractors trailer
being blown over.
But Exposure D is pretty well explained in Section 1616 and has been around
a number of years, so I don't really understand why it comes up from Dennis
at this time.
Neil Moore, S.E.
neil moore and associates
shingle springs, california
At 04:09 PM 6/12/2001 -0700, Jeff Smith wrote:
>I was told by the Belvedere, CA building official to use exposure D.
>Belvedere is located well within the San Francisco Bay. It did not seem to
>me to represent the highest wind exposure, however, it was about 100 yards
>from the water on a steep hill. As it turned out seismic still governed.
>|~|Exposure D is clearly defined with regards to large open bodies of water.
>|~|Large open bodies of sand where not considered by the code writers I am
>|~|sure, and I can see your analogy. If you do not feel that the exposure C
>|~|80mph forces are appropriate, increase the wind speed. There
>|~|are areas of
>* This email was sent to you via Structural Engineers
>* Association of Southern California (SEAOSC) server. To
>* subscribe (no fee) or UnSubscribe, please go to:
>* Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you
>* send to the list is public domain and may be re-posted
>* without your permission. Make sure you visit our web
>* site at: http://www.seaint.org
* This email was sent to you via Structural Engineers
* Association of Southern California (SEAOSC) server. To
* subscribe (no fee) or UnSubscribe, please go to:
* Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you
* send to the list is public domain and may be re-posted
* without your permission. Make sure you visit our web
* site at: http://www.seaint.org