ABSTRACT
Rapid urbanization coupled with scarcity of construction sites forces the foundations of structures to be placed close to each other to meet functional requirements. This leads to a potential overlapping of stressed zones and alter the load-settlement behavior of the system of footings. The footing geometry, spacing configuration, and the type of soil are varied to study the interference effects in terms of the variations of the Bearing Capacity Ratio and settlement ratio with the spacing ratio. Numerical analysis results show that the bearing capacity, and total settlement of an isolated footing are significantly altered by the interference phenomenon. For footings on cohesionless soil and cohesive-friction (c-ϕ) soil media, the magnitude of the ultimate bearing capacity increases as the clear spacing between the foundations decreases. For footings on clay medium, the variation of the ultimate bearing capacity is not significant; however, the permissible bearing pressure corresponding to 50 mm settlement is found to decrease with the decrease in clear spacing. Moreover, the present analyses indicate that the settlement of closely spaced footings is found to be higher than that of a single isolated footing, and the settlement further reduces with increase in the clear spacing ratio. In general, for S/B ≥ 3.5, the load-settlement behavior of each of the adjacent footings is almost the same as a single footing. This study will ultimately be relevant to future endeavors associated with the design of closely spaced shallow foundations in enhancing the bearing capacity, and controlling the deformation of soils.
