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RE: Snow load in combination with seismic.

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What about the legal aspects?  The code more or less only allows the local building official to permit reductions.  If you reduce the load without his/her blessing, what kind of liabilities do you incur?
Perhaps you shouldn't think of it as a "penalty", but as adding conservatism to your design.

Steve W Bigham, PE
Design/Project Engineer
Braden Manufacturing
Ext. 2256

-----Original Message-----
From: William Nelson [mailto:BNelsonSE(--nospam--at)]
Sent: Thursday, June 07, 2001 2:30 AM
To: seaint(--nospam--at)
Subject: Re: Snow load in combination with seismic.

Use 1/3 of roof snow load Pf
Bill Nelson
----- Original Message -----
Sent: Wednesday, June 06, 2001 2:29 PM
Subject: Snow load in combination with seismic.

I have 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.

Bill S. Marczewski
Martin Design, Inc.
1360 S. Clarkson St.
Denver, CO 80210