We used to hold them separate, but we were called on it on a couple of peer reviews. We now add the two loads.
Looking at example 3 of the “Guide to the Use of the Wind Load Provisions of ASCE 7-02” (granted old code, but it is still the same provisions) the two loads appear to be combined. As I was taught, windward = pressure, leeward = suction, in the end they act in the same direction.
Jason Christensen, S.E.
Project Engineer
WCA Structural Engineering, Inc.
From: Michael Liew [mailto:michaelliew4@gmail.com]
Sent: Monday, December 08, 2008 3:32 PM
To: seaint@seaint.org
Subject: Re: ASCE wind on parapets
Joe,
I use 1.5 for the windward parapet and 1.0 for the leeward parapet. I don't combine them.
Michael Liew
On Mon, Dec 8, 2008 at 1:35 PM, Joe Goldbronn <jgoldbronn@barrish.com> wrote:
How are the wind forces on parapets to be applied to the MWFRS (section 6.5.12.2.4)? Are you to apply both the +1.5*q windward and the -1.0*q leeward pressures onto the same parapet? This would in essence create a 2.5*q total force on each parapet of a structure. This seems to be a larger force than I would expect for the parapets which makes me wonder if I am interpreting the code correctly.
Joe Goldbronn, PE