The correct answer is: D. All the above
A column footing is a type of foundation that supports a column or pier. It is typically made of concrete and has a larger surface area than the column or pier, which helps to distribute the load over a larger area of soil. This is important in soils with low bearing capacity, as it helps to prevent the soil from sinking or settling.
A grillage footing is a type of foundation that is made up of a series of beams or girders that are connected together. The beams or girders are typically made of steel or concrete, and they are laid on top of the soil. The weight of the structure is then transferred to the beams or girders, which in turn transfer the load to the soil. This type of foundation is often used in areas with poor soil conditions, as it provides a more stable base for the structure.
A raft footing is a type of foundation that is essentially a large concrete slab that supports the entire structure. The raft footing is typically much larger than the structure itself, and it is designed to distribute the load evenly over the soil. This type of foundation is often used in areas with very poor soil conditions, as it provides a very stable base for the structure.
In conclusion, all of the options (column footing, grillage footing, and raft footing) are types of foundations that are generally provided in soils possessing low bearing capacity.