Numerical Investigation of the Bearing Capacity of Strip and Rectangular Shallow Footings on Cohesive Frictional Soils Under Eccentric Loads

Safe performance of structures founded on shallow footings necessitates that: (a) the ground settlements are kept within acceptable threshold limits; and (b) the bearing capacity is always higher than the imposed stress, by thus giving an acceptable factor of safety. Regardless of minor alterations on the original bearing capacity expression by (Terzaghi K (1943) Theoretical Soil Mechanics. Wiley), most terms are used routinely in engineering practice to date. This paper revisits the bearing capacity of strip and rectangular footings on cohesive frictional soils under eccentric loads, by means of two- and three-dimensional numerical analyses in the finite element code Simulia Abaqus. The geomaterial is described by means of the Mohr–Coulomb failure criterion and works at a null dilation angle, while the footing remains undeformed regardless of the ground stiffness. The ground-footing interface allows for separation and slippage to account for cases where the ground detaches or slips beneath and around the footing. The paper studies the effect of: (a) elastic Young’s Modulus; (b) width; (c) cohesion; (d) surcharge; (e) dilation; (f) strain-softening; and (g) interface roughness on the bearing capacity. The paper shows that the Eurocode 7 underestimates the bearing capacity by up to 60% compared to the numerical solution. Revised bearing capacity and shape factors are developed to enhance the accuracy of the bearing capacity equation.