ASCE7-05 12.13.4

[SteelPE]

ASCE 7-05 section 12.13.4 Reduction of Foundation Overturning

Overturning effects at the soil-foundation interface are permitted to be reduced by 25% for foundations of structures that satisfy the following conditions:
A The structure is designed in accordance with the Equivalent Lateral Force Procedure
B The structure is not an inverted pendulum or cantilever column type system.

How I read this is that I can reduce the seismic loads on my foundation by 25% for load cases with seismic load where the foundations are governed by overturning, sliding or bearing pressure (so essentially uses 75% of the seismic load or 0.7*0.75 for Allowable Stress Design Load Combinations). Is this the correct interpretation?

 

[KootK]

My interpretation is the same. Rationally, I think that should apply to everything below the seismic base if there's below grade structure. I suppose that's another conversation however.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Deker]

That is correct. If your building is one story I would caution against using this provision even though it is technically permitted.