There are various types of deep foundations which can be used in construction. Some of them are piled foundation, pier foundation, shafts and caissons etc.
Pile foundation is the most common deep foundation type which transfers load to the soil by vertical members called piles. These are usually made of steel, concrete or wooden and can be driven into the ground by digging.
There are many types of deep foundations and their applications vary based on the site conditions. The main consideration is the bearing capacity of the underlying soil. In many cases, the depth of the footing should be increased until hard strata are encountered.
Some of the reasons why a geotechnical engineer recommends a deep foundation include very large design loads, poor soil at shallow depth or site constraints like property lines and other factors. The design process for a deep foundation is more complex and more expensive than a shallow one, but in most situations it is the best option.
Other types of deep foundations include drilled shafts, helical piles, and caissons. Each of these can have its own benefits and disadvantages depending on the site conditions and requirements.
Screw piles are another type of deep foundation that have been in use since the mid-19th century. They are galvanized iron pipes with helical fins which are turned into the ground and sized according to the required depth.
These are one of the most effective deep foundations that can be installed in a fraction of the time of traditional methods and provide torque-to-capacity feedback for production control. These foundations also allow for fast and simple construction and are often combined with concrete.
The main advantage of helical piles is that they can be screwed in place instantly so that construction can start immediately without having to wait for the installation to complete. This is a great benefit for large projects that need to move forward quickly.
In areas where there is a risk of earthquakes, this type of foundation can be used to protect the structure and its components. It is also useful for buildings that require large amounts of space below the ground level and have a number of functions.
A pier foundation is another type of deep foundation that is constructed by a series of huge diameter cylindrical columns to support and transmit the huge super-imposed loads from a structure to the firm strata underneath it. These are commonly used in bridges and other structures that need a strong base.
Wells or cassions are also a deep foundation that are often used for water reservoirs and other similar types of buildings. They are built below the surface of the water and help to keep the structure stable.
Basements are a type of deep foundation that is used to provide extra storage or working space below the ground level and are usually hollow substructures with functional requirements in mind. They can be built in open excavations or beneath existing buildings.
