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Re: pre engineered metal building foundations

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     The 1/3 of the stem wall length of bay spacing is a prudent 
     assumption. The UBC 97, Section 1621.1, says that wind load shall not 
     exceed 2/3 of the dead load resisting moment. This allows the FS of 
     1.5 for Overturning.The weight of the backfill could be allowed to be 
     included in the DL resisting moment. If compacted well, which I assume 
     it will be, the weight of the floor slab could also be included. 
     However, base on my experience, I always deduct 1 to 1 -1/2 foot of 
     backfill to consider soil disturbance during construction which leads 
     to loose top soil.
     Jerome Tan

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Subject: pre engineered metal building foundations 
Author:  MIME:murarjm(--nospam--at) at INTERNET
Date:    5/26/98 3:14 AM

I would like some opinions on designing pre engineered metal building 
foundations for uplift and lateral bearing & sliding.  We consider the dead 
load and lateral bearing from 1/3 the stem wall length between bay spacing 
will offer resistance.  ie. 30 ft bay /3 or 10 ft.  The stems and main frame 
piers are cased monolithically and all reinforcement is continuos through the 
piers.  Safety factors (SF) are 1.5 for silding, uplift 2.0 for overturning.  
The soils are usually type 4 Table 18-1-A
Recently we reviewed a foundation plan supplied by a metal building company 
in which they assumed 1/2 the bay for uplift and lateral sliding.  They 
also allowed credit for the backfill material and 4" conc. floor slab and 
SF 1.5 overturning.
Thanks in advance
Joe Murar P.E.