Soil included in .6D of load combination?

[PostFrameSE]

I've got some columns with some pretty significant uplift on them. I've got some building dead load acting on the column of course. When I look at the load combination .6D + W, do I need to look at my soil cone that I'll be picking up as being reduced 40% from the calculated load or does the .6D just apply to the building?

Then............what type of FS is generally used against uplift?

Thanks.

 

[SteveGregory]

I would consider using 30 degrees or less measured from vertical for the soil weight. This is based on the internal angle of friction for the soil backfill. Since it is fill, compaction would be necessary in order to use this angle or else just use the soil directly above the footing.

 

[leeStruct]

From design point of view, I will not argue with not to use 45 degree soil. Most of the time I will probably Take the same design strategy as JAE's, just for play it safe. However, if strictly consider from academic point of view, if the soil internal angle is 30degree, then the soil cone which will behave as dead load to the footing will be at 60 degree from vertical because the footing uplift action to the soil makes the soil in passive rankin state.

 

[MTJJ]

my thoughts, 0.6 for the dead load and soil cone with no factor of safty for overturning, 30 degrees for the soil angle (maybe 45 if I was desporate like a crack addict and had a good geotech dealer). Allowances for footing "suction" is pretty wild and not designing anchor rods for the 0.6D + 1.0W is frightening.