The Construction Techniques of Mat Foundations
Mat foundations, also known as raft foundations, are thick concrete slabs laid on the ground to serve as the structure's foundation. Mat foundations are used in a variety of situations, including the construction of buildings, bridges, and towers.
As superstructure support, a mat foundation is never a flat plate placed on the ground. Based on the application of loads, there is a range of designs.
We build a flat plate to reduce the loads applied to the mat base. However, as the loads grow, other approaches, which are discussed in this article, are added to improve the slab's stiffness. By the use of Mat Foundation, a 10-floor tall building structure can be supported.
Furthermore, a rise in axial loads results in a greater building cost. It may even go beyond the building of pile foundations to a certain extent.
Construction Techniques of Mat Foundation
1. Remove the dirt and excavate the soil to a level that is uniform and flat.
2. The foundation bed is then rammed to make it compact.
3. After compacting, a waterproof sheet is placed on the earth's surface.
4. Pour a 7cm layer of cement concrete mixture on top of that to make a perfectly smooth and level foundation base.
5. Over the foundation bed, place reinforcement on spacers. Steel mesh is used to give reinforcement in both directions. To balance upward and downward bending stresses, two meshes are reinforced at the top and bottom of the foundation.
6. After all of the steel is in place, concrete is poured to the necessary thickness. Which is 300mm thick for modest buildings but can be much thicker if high weights are to be carried. A rebar cover of at least 50mm should be maintained.
7. Finally, to ensure that concrete achieves the specified strength, a proper curing regime should be used.
Utilization of Mat Foundation
1. It is used in the construction of commercial structures. The loads in this instance are frequently large. In locations where basements are common, mat foundations are popular.
2. Mat foundations are also utilized in low-bearing-capacity soils. To distribute the load of a building and thus create a secure foundation.
3. It can also be utilized to reduce the uneven settlement of the building.
4. When the soil layer is unstable, a raft or mat foundation is mostly used. Strip foundations would cover more than 70% of the ground surface beneath the building in this situation. There are other times when the soil layer may shift, which is common in mining areas.
Merits of using Mat Foundation
1. We built a mat slab foundation to produce an economical construction. Such as when the cost of a deep foundation is higher than the cost of a shallow foundation.
2. Because of its high resistance, the building will not slide during a flood or earthquake.
3. The Mat Slab foundation can assist in transferring the building's load to a more stable place.
4. We may save money on materials by using this Mat slab foundation. As the foundation is built at the same time as the ground floor slab is poured, it may save both time and money.
5. Because the mat slab is a shallow foundation, the foundation's depth is reduced, and the foundation's excavation is reduced.
6. The load capacity of the mat slab foundation is greater than that of the other types of foundations.
7. Another advantage of the mat slab foundation is that it can be built on poor soil.
To learn more, watch the following video tutorial.
Video Source: DECODE BD
Demerits of using Mat Foundation
1. For the mat foundation, a higher amount of materials such as steel or concrete were needed.
2. The Mat slab foundation is not appropriate for residential use.
3. When dealing with concentrated loads, a unique measurement is sometimes required.
4. Because the foundation area of the mat slab is enormous, the structure's cost will rise.