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RE: ASCE 7-98 Vs. ASCE 7-95 (Wind Provisions)

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-----Original Message-----
From: Mauricio A. Lopez [mailto:mal1473(--nospam--at)hotmail.com]
Sent: Wednesday, May 30, 2001 10:11 AM
To: seaint(--nospam--at)seaint.org
Subject: ASCE 7-98 Vs. ASCE 7-95 (Wind Provisions)

We plead to the county officials and their response was:   If you can prove that the 98 edition is safer than 95 edition, they will allows us to use the 98 edt., otherwise the 95 edt. must be used.
It's not so much that the wind PRESSURES changed, but the basic wind SPEEDS were changed slightly from 1995. IIRC, this is the result of ongoing stochastic modeling of storm events over a long period of time (well, as long as humans have been keeping accurate records anyway, maybe one hundred years). I think that was the purpose of the change.
 
7-95 is, as I recall, slightly more conservative than 7-98, but 7-95 isn't much different, once you massage the numbers, from the results you'd get applying 7-93. The biggest change there was the switch from "fastest mile" to "three-second gust" in conformance with a change some years prior in the method by which meteorologists actually measure wind speeds for record purposes.

William L. Polhemus, Jr., P.E.
Polhemus Engineering Company
Katy, Texas
Phone 281-492-2251
Fax 281-492-8203