As the name suggests, deep foundations are foundations that extend to greater depths to support the structure. Generally, deep foundations are constructed with materials such as concrete, rebar, steel, wood, or a combination of these materials.
What is a deep foundation?
A deep foundation is a foundation that extends to a greater depth where there is a hard layer of earth that can support the loads that occur, or continue up to or into the rock, as specified in the design.
The following Types of Foundations can be listed as the main types of deep foundations.
- Pile foundations
- Pillar foundations
- Pit or caisson foundations
- diaphragm walls
Let's discuss each type of foundation in detail.
Pile foundations
Pile foundations are the most commonly used foundation type, deep foundations in construction. In the construction of bridges, buildings, road structures, etc., mainly hollow-in-situ piles or prefabricated concrete piles are used.
Pile foundations can be classified according to their load capacity or type of anchorage.
- Final stakes
End piles are piles that support the applied load through their end bearing capacity.
In addition to final storage, the surface friction of the pile also increases its load capacity. Fresh rock and weathered rock have high friction, which must be taken into account in pile design.
- Friction piles
When higher axial loads occur and the rock is very deep, skin friction is used to support the applied loads. With these piles, the load capacity of the end support is lower due to the smaller cross-sectional area.
The method for calculating end bearing and hull friction is described in the article Pile Foundations . For more information, contact us.
- Anchored piles
Furthermore, pile foundations are categorized according to the material they are made of.
- Concrete piles
- steel piles
- wooden posts
- Composite piles
The most common type of pile foundation is concrete piles. Almost all tall buildings are constructed on in situ concrete pile foundations. They have greater structural and geotechnical load capacity compared to other types of piles.
On the other hand, sheet piles are not load-bearing piles. They are commonly used as support structures. The common use of sheet piling is temporary support, permanent sheet piling, etc.
Previously, wooden posts were used. Today, with alternative materials available such as steel and concrete, these are no longer used. Furthermore, the durability of wooden posts is an aspect that we must take into consideration during construction.
Pillar foundations
As the name suggests, pier foundations are deep foundations with a larger diameter. A normal pile has a shallower depth compared to the pier foundation.
In modern construction there are larger piles with a diameter greater than 3,000 mm.
Pillar foundations are constructed as wall piles or concrete piers. The concrete pillar can be of the box type or another.
Furthermore, there may be uncoated columns with only a visible concrete surface.
Pit or caisson foundations
The use of this type of deep foundation is not common. This type of foundation is only used on special occasions.
A pit or caisson foundation is a type of foundation with a covering for the internal materials.
In addition, the foundation caisson can be made of steel, concrete or any other material.
For more information, you can refer to the following type of deep foundation or other types of foundations.
- Design and construction of foundations using driven piles
- Pile design (draft detailed instructions)
- Stack Design (Things to Remember)
