IBC & ASCE Overturning Factor of Safety

[jike]

I have reviewed the previous threads on this subject (all regarding UBC) and wasn't able to find the answer for the IBC specifically.

Is there a recommended minimum factor of safety for foundations subject to wind overturning (governed by the IBC)? I cannot find anything in IBC, Chapter 18. In ASCE 7-98, one of the basic load combos is 0.6+ W. Is this meant to govern overturning (FS = 1/0.6 = 1.67)?

I have always used FS = 1.5.

Can anyone refer me to the proper section of IBC or ASCE that spells this out?

 

[whymrg]

IBC 2000 p.313 sec.1610.2 retaining walls: "Retaining walls shall be designed for a safety factor of 1.5 against lateral sliding and overturning."

 

[jike]

I am a little surprised to see 1.5 FS for both overturning and sliding. I am used to using 2.0 for overturning, 1.5 for sliding and 1.5 for overturning with wind.