The primary purpose of a building's foundation is to transfer the weight of the superstructure to the ground. An isolated footing is a commonly employed foundation type for supporting individual columns, especially when they are spaced at a considerable distance.
The design of an isolated footing ensures that it does not exceed its load-bearing capacity, preventing overturning or sliding and also preventing the ground from settling. Isolated footings are most cost-effective when the mechanical properties of the soil beneath them remain relatively consistent, i.e. in the case of good homogeneous soil. Isolated foundation footings fall into the following categories:
A pad or flat isolated footing is typically made of plain or reinforced concrete and can have a circular, rectangular, or square shape. It is a cost-effective option that requires minimal excavation. However, its size is determined by the applied load, and it offers limited resistance to lateral forces.
Sloped isolated footings, also known as trapezoidal footings, use less concrete and reinforcement bars compared to pad footings. They are constructed with a careful 45-degree slope from all sides. To prevent excessive deformation, a stiff concrete mix is used.
Stepped footing involves constructing the footing incrementally until it reaches the desired width. In fact, three concrete cross-sections are stacked upon each other to create the steps. While it has traditionally been used in residential buildings, its popularity has declined in recent decades.
As structures are getting more complex, foundation designing is becoming more challenging. Foundati...