Types and Advantages of Raft Foundations

A raft foundation is a strong concrete base that helps hold up bridges, buildings, and other construction structures. The flat block of the Raft foundation helps to spread the overall weight of the construction structure, as a result, the construction structure does not sink into the ground. This type of foundation is normally used in such places where the soils are like soft clay or sand. Raft foundations are floated on the soil and it is useful in the case where the other types of foundations do not work properly.

A thick and strong piece of concrete which is held up by the grid of steel bars is used for constructing the Raft foundation. The thick and strong nature of the Raft foundation helps to prevent bending or broken incidents due to the heavy weights thus preventing the sinking of the construction structure into the ground. The thickness and deep nature of the Raft foundation is depended upon the nature of the ground and the load of the construction structure.

Materials that have been used for constructing the Raft Foundation

? Concrete is mainly used to construct the raft foundation. In this case, steel has been reinforced this foundation to enhance the strength and durability of the foundation structure. ? For reinforcing the concrete of the raft foundation, a steel bar has been used. These materials help to add strength to the foundation structure thus handling the tensile stress. ? Wood, plastic or metal is also used by the builders for making formwork which acts as a temporary mold and provides shapes to the concrete. ? A waterproofing membrane has been also applied to the Raft foundation’s surface which helps to prevent water ingress. The use of a waterproofing membrane is important in those areas where groundwater level is high.

The process of constructing the Raft Foundation

The preparation of the site

This is the first step of constructing a foundation, in which, the debris is cleared, and the grounds have been levelled which helps to ensure a stable base for the raft foundation.

Installation of the formwork

After preparing the site, the formwork has been installed to contain the concrete. In this case, formwork has to be strong and stable to maintain the proper shape of the concrete until the concrete has hardened.

Reinforcement

Builders are involved in laying the steel bars in the formwork. This reinforcement helps to provide the strength to the foundation which is needed for supporting the foundation’s load.

Concrete pouring

The next step for making the raft foundation is pouring the concrete into the formwork. After pouring the concrete, it has been spread evenly which helps to ensure that there is no gap or void in the concrete.

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