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Factor of safety relative to sliding and overturning

Factor of safety relative to sliding and overturning

Factor of safety relative to sliding and overturning

I am in the process of verifying some structural calculations performed by an outside organization for a client.  
The specified codes are 1997 UBC, ASCE 7, AISC, etc.  I remember the factor of safety relative to sliding and overturning is 1.5, however I have not been able to substantiate that number.  I need to be able to "point" to a particular section of these "design codes" for my response but for the life of me can't find it.  If I remember correctly the statement that I am looking for regarding overturning is expressed as an equation that is the inverse of 1.5, or 2/3, and that the statement reads something like the "the ratio of the overturning force compared to the resistive force shall not exceed 2/3".  It sure seems that the resistance to sliding is on the same order.  

Can someone point me to the correct section(s) of the design codes where these FSs comes from?

RE: Factor of safety relative to sliding and overturning

I'm not sure if this is the one your mentioning.

Second paragraph of Section 1621.1, UBC 1997 Volume 2, page 2-7.


RE: Factor of safety relative to sliding and overturning

Thanks edba!  
I looked past it several times in my search, one of the guys that I work with ordered some reference material prior to my arrival and did me the dis-service of purchasing UBC on CD!  
Personally, I like the paper version much better!  and the paper version of volume 2 is on its way!

Does anyone have an idea regarding the resistance to sliding FS?


RE: Factor of safety relative to sliding and overturning

Perhaps common codes do not have the 1.5 SF. Our Florida Building Code 2001 has no SF for most of the state, but: Thanks to our recently retired County Building Official, Jaime Eisen, the High Velocity Hurricane Zone portion has the 1.5 SF in Ch 1620. We had it locally before the State took over.

The AASHTO code, Interum 1991, that I worked under years ago had a table, Table Recommended Factor of Safety on Ultimate Geotechnical Capacity Based on Specified Construction Control. Being factored loads the SF varied from 3.5 to 1.9.

RE: Factor of safety relative to sliding and overturning

The only printed code that specifically states 1.5 times the lateral force and 1.5 times the overturning moment is in UBC 1611.6 (I believe this is a ACI recomendation) and pertains to retaining walls.

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