Bearing capacity of strip footings on purely frictional soil under eccentric and inclined loads

Abstract

The finite element method is used for the determination of the collapse load of a rigid strip footing placed on a uniform layer of purely frictional soil subjected to inclined and eccentric loading. The footing is set on the free surface of the soil mass with no surcharge applied. The soil is assumed to be elastic – perfectly plastic following the Mohr–Coulomb failure criterion. Two series of analyses were performed, one using an associated flow rule and one using a nonassociated flow rule. The first series is in accordance with bearing capacity solutions currently used in shallow foundation design practice, while the second one is consistent with the dilatancy exhibited by sands in reality. Both probe-type analyses and swipe-type analyses were undertaken. Analyses for associated and nonassociated flow rules yield essentially the same trends regarding the effective width, inclination factor, and normalized vertical force – horizontal force – moment (V–H–M) failure envelope. The results show that the inclination factor depends on the value of the friction angle, whereas the effective width does not.