Joe,
These are net pressures, so essentially 1.5*q is your worst case rocking the parapet onto the building and q is the worst case trying to topple it off the edge.
regards,
Gordon Goodell
From: Joe Goldbronn [mailto:jgoldbronn@barrish.com]
Sent: Monday, December 08, 2008 2:35 PM
To: seaint@seaint.org
Subject: ASCE wind on parapets
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