Limit load of surface foundations

Vesic

Project limit load in short term

In order that a foundation may safely sustain the projected load in regard to general rupture for all combinations of load relative to the ultimate limit state, the following must be satisfied:

where:

Vd is the project load at ultimate limit state normal to the footing, including the weight of the foundation itself;

Rd is the projected foundation ultimate limit load for normal loads, also taking into account eccentric and inclined loads. When estimating Rd for fine grained soils short and long term situations should be considered.

Limit load undrained conditions is calculated by:

where:

	Project effective foundation area. There where eccentric loads are involved, use the reduced area at whose center the load is applied.
cu	Undrained cohesion.
q	Total lithostatic pressure on footing.
sc	Foundation shape factor.
	Rectangular shapes.
	Strip foundations
	Correction factor for inclination of load H.
	Depth factor.

Project limit load in drained conditions is calculated as follows:

where:

Form factors

	Rectangular shape
	Rectangular shape
	Rectangular, square, or circular shape

Resultant inclination factors due to an horizontal load, H parallel to B'

Depth factor.

Hansen

Project limit load in short term

Limit load undrained conditions is calculated by:

where:

	Project effective foundation area. There where eccentric loads are involved, use the reduced area at whose center the load is applied.
cu	Undrained cohesion.
q	Total lithostatic pressure on footing.
	Strip foundations
	Correction factor for inclination of load H.
	Depth factor.