Existence of moment or eccentricity is a common loading situation; thus, it is necessary to be totally aware of the circular footing bearing capacity subjected to eccentric load to design economically. This paper presents a design chart for transforming a circular footing under eccentric load into an equivalent rectangular footing, allowing the use of existing bearing capacity formulas. A new “effective area” is defined, and characterized by a uniform soil pressure distribution. Unlike previous methods, the paper fully describes the calculation process for this area. The results show significant differences in the dimensions of equivalent footings compared to older methods, especially in designs with low eccentricities, leading to higher bearing capacities. Additionally, the dimensions of the “contact area,” which fully interacts with the soil, are derived to ensure compliance with building codes. Finally, simple mathematical expressions for eccentricity reduction factors are provided for both drained and undrained conditions.

Keywords