In section 1807.2.3 Safety factor the wording has not changed between the 2009 IBC and the 2012 IBC. It reads:
Retaining walls shall be designed to resist the lateral action of soil to produce sliding and over-turning with a minimum safety factor of 1.5 in each case. The load combinations of...
I work in telecom and oftentimes we put new structures on existing rooftops. We use Figure 29.5-1 (for "Chimneys, tanks, rooftop equipment, & similar structures over 60') a LOT as it's the best description of the kind of work we do much of the time. The question is what do "h" and "D" really...
