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FW: ASCE 7-98 Wind Provisions

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Addendum to this post:

The 15-20% reduction applies to elements NOT in areas of discontinuities,
and the elements in question are wall elements.  Wall corner suction
pressure for 7-98 is 20-25% GREATER than for UBC94.

T. Eric Gillham PE

-----Original Message-----
From: T. Eric Gillham PE [mailto:teric(--nospam--at)gk2guam.com]
Sent: Monday, March 19, 2001 10:16 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: ASCE 7-98 Wind Provisions


I've finished a run through of ASCE 7-98's wind loading provisions for a
project here on Guam.  I was comparing the wind loading requirements for
UBC94 (still our current code), ASCE 7-95 and 7-98, and found out that 7-98
results in a 15 to 20% reduction in service level design wind pressure for
components and cladding in structures with h>60 ft.

The main reason, I think, is the change in exposure category for shorelines
in hurricane prone regions.  These areas are now specifically categorized as
C, as opposed to D in 7-95 and UBC94 (by default, really).

Our building department is currently in the process of adopting the IBC,
which will make ASCE 7-98 an official code document.  I was wondering if any
other engineers in hurricane prone areas are aware of their building
departments changing to IBC, and the possible ramifications of the reduced
design wind pressures (assuming I did the calcs correctly, but I'm pretty
sure I got it right).

This is a concern for us, because there have been many instances of windows
in hotels here (not ours :) ) being blown in/out during typhoons, right up
to 1998.  Granted, airborne debris and shoddy construction may have been
contributing factors, but it happened none the less.

If anyone on the listserver is aware of this issue coming up wrt their local
code, I would appreciate any comments.



T. Eric Gillham PE