ASCE 7-10 Snow Load Drift Height
ASCE 7-10 Snow Load Drift Height
(OP)
When calculating the drift height and width per Section 7.7.1 I'm confused by this statement:
"If this height exceeds hc, the drift width, w, shall equal 4hd2/hc and the drift height shall equal hc."
So, what value of hd is used in the equation for w? The value calculated in Figure 7.9 OR the value of hc, making w=4hc2/hc.
"If this height exceeds hc, the drift width, w, shall equal 4hd2/hc and the drift height shall equal hc."
So, what value of hd is used in the equation for w? The value calculated in Figure 7.9 OR the value of hc, making w=4hc2/hc.






RE: ASCE 7-10 Snow Load Drift Height
RE: ASCE 7-10 Snow Load Drift Height
RE: ASCE 7-10 Snow Load Drift Height
Are you all saying that the "hd" in 7-10 is calculated by formula rather than derived from a Figure 7-9 as in 7-05?
I DO need to purchase ASCE 7-10 since Wisconsin is destined to adopt it.
RE: ASCE 7-10 Snow Load Drift Height
BSVBD; no, both ASCE 7-05 and ASCE 7-10 use Figure 7-9 to determine hd. There is an equation for hd included within Figure 7-9 but that is true for both ASCE 7-05 and ASCE 7-10 and the equation is identical in both standards.
RE: ASCE 7-10 Snow Load Drift Height
RE: ASCE 7-10 Snow Load Drift Height
RE: ASCE 7-10 Snow Load Drift Height
In 7.8, ASCE inadvertently defines an applicable projection as something greater than 15' wide.
But, how TALL is the projection? And is the projection a parapet wall?
If either the projection or parapet is too tall, we would then not consider the leeward drift.
I would say, in most cases, a projection would cause a windward drift.
Within project specific reason and judgment, unless one "greatly" outweighs the other, why not take the conservatively larger of the two?