Subject: RE: Snow load in combination with seismic.
From: Charles Espenlaub <Cespenlaub(--nospam--at)martinaia.com>
Date: Wed, 6 Jun 2001 17:36:14 -0400
would think it would depend on the roof and building configuration. With a
flat roof with parapets, where the snow has no where to go, I would use
100%. But if you have sloped roof, and the seismic event might cause the
roof to "shed" some of the snow, you may be able to use a lower
percentage. However, with this reasoning, and low roof might then get a
lot of snow dumped on it.
my two cents.
Charles F. Espenlaub, III, P.E. Martin-Espenlaub Engineering Tel 215-665-8570 Fax
-----Original Message----- From: Bill Marczewski
[mailto:bmarczewski(--nospam--at)martind.com] Sent: Wednesday, June 06, 2001 5:30
PM To: 'seaint(--nospam--at)seaint.org' Subject: Snow load in combination
a multi-story building with high snow loads located in a very low seismic region
(zone 1). The building official is unable to provide information regarding
the percentage of snow load in excess of 30psf that should be used in
combination with the seismic load. My preliminary calculations consisted
of using 100% of the snow in the seismic dead load, and I feel this is a
significant penalty. I have previously been able to use only 25% of the
snow load in seismic zone 3 in Jackson, Wyoming. On the other hand,
Steamboat Springs, Colorado (zone 1) has required 100% of the snow load to be
used in combination with the seismic load. The 1997 UBC states that snow
loads beyond 30psf must be considered in seismic design, but may be reduced up
to 75% when approved by the local building official. What should I do, or
does anyone have any recommendation on what percentage of snow to use when the
building official cannot provide guidance on this issue? I think the
use of 100% snow load in combination with seismic is really to harsh.
Comments would be great. Thank you.