Raft or Mat Foundation: A beneficial construction article

When the soil has a low bearing strength, raft or mat foundations are usually recommended to support weighty structural loads. Moreover, raft or mat foundations are the most suitable in situations where the structure is likely to collapse due to its location in a mining area or unpredictable sub-soil water conditions.

Raft or Mat Foundations offers a cost-effective solution to complicated site conditions, where the development process is not convenient for pile foundation, the separate column footing turns out to be unfeasible.

In raft or mat foundations, the base is made up of a rigid concrete slab covering the entire bottom area of the structure in a similar manner to what is used in floors. The slab is reinforced with bars located at right angles to each other both adjacent bottom and top faces of the slab.

It is often required to bear the extreme column load by organizing inverted main beams and secondary beams which are formed monolithically with the raft slab.

Process related to construction

An average span of 30 cm is usually set for the raft slab when it is developed. Since a portion of the excavation range extends over the area of the structure itself, all sides of its exterior walls can be excavated.

Once the excavation is complete, compaction can be completed flawlessly and a desired depth can be reached in the excavated area. When the surface has dried, it is possible to lay the raft or mat slab over it. It is imperative that all necessary safety precautions be taken during the construction of the reinforced concrete structure. In order to ensure a successful construction, some precautions needs to be maintained, and the raft needs to be cure before the construction can begin.