When the soil’s bearing capacity is insufficient to support a structure, a pile foundation is necessary. The choice of pile foundation is based on several factors, including soil conditions, types of loads, bottom layers of soil, site conditions, and operational conditions. Pile foundations typically consist of a pile cap and piles that may be present individually or in groups. Piles serve the critical function of safely transferring the loads from the superstructure to the hard strata, soil, and rocks below. These piles are typically long, slender members that can be over 15 meters in length.
The pile foundation’s importance in construction is due to its various functions. Pile foundations play a crucial role in ensuring the stability and safety of structures by providing a solid foundation on unstable soil. They distribute the load evenly, which reduces the likelihood of settlement, tilting, or collapsing of the structure. Additionally, pile foundations are useful in areas where the soil is prone to liquefaction or where the water table is high. They also minimize noise and vibrations, which is beneficial in densely populated areas. Overall, pile foundations are essential for ensuring the long-term structural integrity of buildings and infrastructure.
When and Where Pile Foundations are Used?
Pile foundation is a type of foundation that is exclusively used in certain construction sites where specific needs must be met. One of these needs is when the structures being constructed are large and heavy, and the soil beneath them is weak. In such cases, pile foundation provides the necessary support for the structures.
In areas where soil liquefaction or water table issues are common, settling can occur, making pile foundation a better choice. The high sub-soil water table at a site can also make the use of other foundations impossible. Pile foundations can penetrate through the water and extend until a hard stratum is reached.
Pile foundation is also necessary for structures that may be subjected to horizontal forces that can affect the foundation. It can resist bending action and support vertical loads, making it ideal for the construction of earth water retaining structures and buildings highly subjected to lateral (earthquake and wind) forces.
Uplift forces created due to water table rise or other causes require pile foundation in structures such as transmission towers and offshore platforms. In areas where soil erosion is possible, shallow foundations may not be sufficient. Pile foundation can help resist soil erosion and eliminate differential settlement in cases where the plan of the structure is irregular, and the load distribution is not uniform.
Pile foundation is also necessary near deep drainage and canal lines. The adjacent soil can be confined using sheet pile foundation.
Functions of Pile Foundation
The pile foundation plays a crucial role in the construction of structures by ensuring the safe transmission of loads to the ground. This transmission is necessary regardless of whether the loads are vertical, horizontal, or inclined. To achieve this, the foundation can be constructed in cohesionless soil through techniques such as displacement and vibration methods.
Another important function of pile foundation is to reduce settlement, which is essential for maintaining the stability of the structure. Additionally, the use of pile foundation can help to increase the factor of safety of heavy load structures or buildings.
By providing safety, security, and reliability to the vertical structures above, the pile foundation guarantees the stability of the entire structure. This is achieved through the proper arrangement of piles and pile caps, which ensures that the load distribution is performed uniformly.
In summary, the pile foundation serves multiple functions in construction, including load transmission, settlement reduction, increased safety, and uniform load distribution. Its importance cannot be overstated, as it ensures the stability and longevity of the structures built upon it.