Interference of Two Closely-Spaced Footings on Finite Sand Layer

Abstract

Bearing capacity of footing is influenced by the presence of adjacent footing. In this study, two closely-spaced strip, square, and circular footings are modelled in finite elements using commercially available software – PLAXIS 2D and 3D. Analysis is done considering both smooth and rough footing bases. The effect of spacing between the footings is examined for footings resting on both semi-infinite and finite sand layers. In addition, angle of shearing resistance of foundation soil is varied from 30° to 40° to investigate its effect on the bearing capacity. Bearing capacity of footings with rough base are found to attain a peak value at a particular spacing indicating the “blocking effect”. For square and circular footings, interference due to spacing is found to be insignificant compared to strip footing. Interference factors for rough footings are found to be higher than that for smooth footings.