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Re: ASCE 7-95 Wind Loads

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I disagree with Roger.  Some guidance on this question can be gleaned from
ASCE 7-95, Figure 6-6, which refers to multi-span gabled roofs.

Note that the valley edges of the 'single-module' are all considered as zone
2.

Lew Midlam, PE
http://www.lcm.com

-----Original Message-----
From: Roger Turk <73527.1356(--nospam--at)compuserve.com>
To: seaoc(--nospam--at)seaoc.org <seaoc(--nospam--at)seaoc.org>
Date: Friday, May 15, 1998 1:18 PM
Subject: ASCE 7-95 Wind Loads


>I believe that the requirements for wind loading at ridges is because
ridges
>(or any other obstruction) causes high localized uplift forces.
Depressions
>(valleys) do not do the same thing.
>
>I investigated the wind damage to a flat roofed, three story motel in which
>the rigid insulation and roofing had been torn off.  Large areas of damage
>occurred immediately downwind from small (1" diameter) electrical conduit
>that was installed across the roof.
>
>A. Roger Turk, P.E.(Structural)
>Tucson, Arizona
>
>Robert Rollo wrote:
>
>. > I need additional opinions . . .
>. >
>. > Wind loads per AISC 7-95.  Hipped roof (3:12) building in a "T"
>. > configuration.  The standard now (versus 93) identifies the hip ridge
>. > condition as a zone 2 "components and cladding" region for pressure.
>. >
>. > How about the 2 valleys created by the "T" shape?  should these have a
>. > zone 2 defined by the "a" width?
>. >
>. > I have one 2 "yes" and 2 "no" votes on this one.  Additionally, the
>. > widths are different as are the eave heights, so I have different
widths
>. > and "h" values.  Are there 2 seperate "a" zone widths, or does the
>. > larger always apply (that would certainly be the conservative
approach)?
>. >
>. > Thoughts anyone?
>. >
>. > Thanks in advance . . .
>
>