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Re: Wind Speeds for design wind pressures

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There is also a discussion and example in the USACE's "Shore
Protection Manual" (1984 still).

-----Original Message-----
From: Harold Sprague <hsprague(--nospam--at)>
To: 'seaint(--nospam--at)' <seaint(--nospam--at)>
Date: 20 July, 1998 11:01 AM
Subject: RE: Wind Speeds for design wind pressures

You have 2 different problems.

I do not know why you would convert a 3 second gust to a 60 minute
wind, but the commentary of the ASCE 7-95 contains the Durst curve and
the Krayer-Marshall curve for a direct conversion.  I have done
conversions to and from 60 second winds (Saffir-Simpson hurricane
winds) and 10 minute winds (WMO standard extreme winds), but never to
a 60 minute wind.

The conversion from 3 second to a fastest mile wind is an iterative
solution, and can also be done using the ASCE 7 commentary, but it is
a bit tricky.  The Structural Engineering Institute's newsletter
contained an example by Jim Rossberg of this iterative procedure.

I would be a bit wary of the API standard.  Rely more on the ASCE 7
for wind load development.

Harold Sprague, PE
Krawinkler, Luth & Assoc.

-----Original Message-----
From: Allan Hickey [SMTP:ahickey(--nospam--at)]
Sent: Monday, July 20, 1998 6:46 AM
To: Seaint@Seaint. Org
Subject: Wind Speeds for design wind pressures

Can any one advise of a conversion for the equivalent 3 second gust
velocity to a specified 60 minute or fastest mile wind velocity. This
is to
convert an API code provision to Australian conditions where we design
shorter duration gust loads which are obviously statistically a
higher number.
Thank you
Allan Hickey, Brisbane, Australia