19 Oct 09 13:22
Here is the relavent paragraph from the UFC. I cannot find similar verbiage in the IBC, except for retaining walls specifically. Hmmmm
1-12. STABILITY. The building foundation must be capable of safely transferring all vertical
and horizontal forces, due to specified design load combinations, to the supporting soil or rock.
The mechanism used for the transmission of horizontal forces may be friction between the
bottom of the footing and ground, friction between the floor slab and ground, and /or lateral
resistance of soil against vertical surfaces of grade beams, basement walls, footings, piles, or
pile caps. Net upward forces on footings and piles, which must be resisted to prevent
overturning and/or flotation, will be considered in the foundation design. Dead load should
include the benefits of weight of the overlying fill in resisting sliding, overturning, and flotation.
Structures will be designed to resist overturning effects caused by seismic forces in
accordance with TI 809-04. For load combinations other than earthquake when load
combinations applicable to allowable stress design (ASCE 7, paragraph 2.4.1) are used for the
foundation design, the building will have a minimum safety factor of 1.5 against sliding,
overturning, and flotation.