Thursday, November 8, 2007

snow drift and adjacent buildings

Listers, i have a question regarding snow drifts and adjacent buildings.
 
Section 7.7.2 of ASCE 7-05 states "The seperation distance, s, between the roof and adjacent structure...shall reduce applied drift loads on the lower roof by a factor of (20s)/20 where s is in ft." 
 
So, w/ Figure 7-8 as a reference, where would s come into play?  Would it be added to the length of the upper roof, Lu.  Or is it part of the width of the drift, w?  Or do i calc the drift as if the building were tight agaisnt each other, as shown in Fig. 7-8, and just reduce the drift load by a factor of s?
 
Does that make sense to anyone?