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PEMB Foundation Uplift

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I designed a foundation for a PEMB.  I want to know peoples methods for designing the footings for uplift.  I have typically designed the footing to weigh as much as the net uplift load (0.6D+(W or 0.7E)).  The calculated net uplift force has a factor of safety of 1/0.6 = 1.67 in it from the reduction of the dead load. I received a plan check comment that states that with my calculations there is only a factor of safety of 1.  But this is a factor of safety of 1 in regards to the net uplift force.  Should we really be increasing the footing weight to maintain a factor of safety = 1.5 over the net uplift force?  To me this is more like a factor of safety of 1.67*1.5 = 2.51.  Not to mention we know what the actual weight of the footing will be.  This is a commercial building and the city inspectors are very good in requiring construction matches the plans, especially foundations.  Am I wrong?  Do others design PEMB footings that weigh 1.5 times the net uplift force?

Thanks in advance for your replies

 

Jeff Hedman