foundation with two way eccentricity

[sme75]

I have a column with uplift and horizontal reactions in two directions at the base. I would like to size the footing to resist the uplift and keep the dimensions as small as possible. I have a copy of Principles of Foundation Engineering by Braja M. Das that I am using to calculate the effective bearing area and soil bearing pressures. My question is, besides the bearing capacity of the soil, what else should I be concerned with in sizing the footing? At what point does this become unstable? Do you think that the footing is acceptable as long as I maintain an adequate factor of safety against overturning on the individual footing? Say (OTM)/((FTG WT) x FTG LENGTH/2)) > 1.5

 

[DaveAtkins]

Also maintain an adequate factor of safety against sliding.

DaveAtkins

 

[UcfSE]

Keep your resultant within the Kern distance.

 

[WillisV]

Not necessary to keep within the kern - as long as the bearing pressure under the reduced bearing area is acceptable.

 

[jjeng2]

I usually look at eccentrically loaded footings similar to a retaining wall foundation which that book you have cover very well. You have max bearing pressure at the "front" to check(two dirs in this case). Uplift on the "back". Overturning. I doubt sliding will be an issue if you dont have lateral force. Besides that, the footing itself needs to be designed. For this, you probably should look at a concrete book.