Bearing Capacity of Interfering Strip Footings

Abstract

In this paper, the ultimate bearing capacity of two closely spaced rigid strip footings with rough base on granular soil is examined based on enhanced limit equilibrium, plastic limit analyses, and finite-difference solutions. The enhanced limit equilibrium and plastic limit analyses are developed on the basis of two proposed failure mechanisms in association with an optimization algorithm. The limit analysis is conducted by using the kinematic element method (KEM), and finite-difference package is used for numerical simulations. The efficiency factors of bearing capacity are calculated at various spacings between two neighboring footings for practical range of friction angles (25°≤ϕ≤4°) in accordance with different solutions. Thereafter, the results obtained from the proposed solutions are compared with those reported from existing experimental, theoretical, and numerical studies. In addition, the reliability of the proposed mechanisms is justified through a series of comparisons with the failure patterns and the shear bands obtained from numerical simulations at different spacings. These comparisons indicated that despite the relative simplicity of proposed solutions, bearing capacities and failure patterns are in excellent accordance with numerical, analytical, and experimental results.