What Is Pile Foundation?
A pile foundation is a deep type of foundation. A pile foundation can be made using long, thin, columnar elements. The pile foundation can be made using steel, reinforced concrete and wood as a material. The depth of this type of pile foundation is three times its width.
Pile foundations can be used from different types as required in building construction.
If the bearing capacity of the ground is low, then it is advisable to take a deep foundation for the structure of the building for the purpose of achieving a strong bearing stratum for the foundation of the building.
The most common types of deep foundations for building are as follows,
- Pile foundations
- Cassions foundation
Various types of pile foundations are used as required to transfer the structural load coming from any building to the desired depth in the ground. This pile foundation has the desired ability to transmit loads of the structure to the desired depth.
The function of a pile is the same as the function of a column. In which the load of the structure has the ability to transmit from the upper level to the lower level. But in the formation of the piles’ foundation, the bulbs are provided at a lower level in the ground so that there is no concern regarding buckling in the pile foundation.
The pile separates from the column in terms of this type of special function. The pile is relatively long per column. The pile can be formed by being driven into the ground. The pile foundation for any building consists of a number of piles. All the piles together support the structure of the building.
Uses of Pile Foundations
Pile foundation is selected in different following situations.
- The pile foundation is used when the load from the building’s superstructure is very high, and its distribution is uneven.
- Pile foundation is used when the bearing capacity of the soil is low where high rise building is to be constructed.
- The problem arises for shallow foundations when the groundwater is high in the ground of the site location for the building. Pile foundations are used when it is difficult and non-economical to pump water from a ditch frequently.
- The use of pile foundation is suitable when there is a big fluctuation in the ground water level in the ground above the site for building.
- Pile foundations are used when canals or deep drainage lines are a barrier to the foundation of a building underground.
- The pile foundation is suitable to be used for foundation of the building on the beach or in the river area. Also where there is a risk of water impact in abundance.
- The pile foundation can be selected when the soil on the site for the building has an expansive nature.
- The pile foundation can be used as a foundation for power transmission towers. Due to the height of this type of tower, it can be used to resist lifting forces.
Types of Pile Foundations
(A). Types of pile foundations depending on the function or uses
1. End Bearing Piles
In this type of pile, the lower end of the pile is lowered into the ground up to the level of strong ground or rock. The load of the structure of the building is transferred to a stronger level by the bearing pile. This type of pile acts as a column. This type of pile transfers the load of the structure from a weak layer to a strong layer.
2. Friction Piles
In this type of pile, the load of the building is transferred to a strong soil strata using skin friction along the length of the piles.
Friction pile is a type of pile foundation. Is the foundation. This type of friction pile transfers the superstructure load of the building to the ground using the force of friction resistance between the surface of the pile and the adjacent ground.
Depending on the subsoil strata position the friction pile can be designed to the required length.
3. Compaction Piles
When the bearing capacity of the soil is low, the pile is driven into the soil for the purpose of increasing the bearing capacity. Piles drilled in this way are known as compaction piles. This type of compaction pile carries no load. So compaction pile can be made from any lightweight materials.
4. Tension Piles
This type of tension pile is used to provide stability to the building and to resist hydrostatic pressure or the moment of overturning. This type of pile foundation is also called an uplift pile.
5. Anchor Piles
Anchor pile is used to transfer compressive and tensile forces to bending moments on the ground safely. Anchor pile is suitable for offshore moorings, basements, and tunnels etc.
6. Fender Piles
Fender piles are typically used to protect coastal structures from ships or other floating objects.
7. Better Piles
This type of pile is used to resist horizontal forces or inclined forces.
8. Sheet Piles
This type of pile is used as bulkheads or as an impermeable cutoff for hydraulic structures to reduce seepage and erection.
This type of pile is used as retaining wall support for docks, wharves, and other marine structures.
(B). Types of pile foundations depending on material and composition
1. Precast Concrete Piles
Precast concrete piles are made in a factory away from the construction site. And this finished precast concrete pile is driven to the ground at the site for buildings. Heavy pile driving the machinery is commonly used for this type of pile foundation.
Precast concrete piles can be made in cross-section into square, octagonal or round shapes. This type of pile is made strong enough to withstand driving stress and handling stress.
The size of this type of pile can be made from 30 cm to 50 cm in cross-sectional dimensions and 20 m in length.
This type of pile uses reinforcement of 20 mm to 32 mm diameter of 4 to 8 nos.
Reinforcement of 8 to 10 mm diameter is constructed as a spiral ring. In which the spacing of the spiral ring is reinforced over the entire length of the pile at 100 mm C / C.
A concrete cover of at least 50 mm is provided for reinforcement in this type of pile. The minimum grade of concrete for pile should be M20
2. Cast -In-Situ Concrete Piles
For cast-in-situ concrete pile is drilled on the site by a boring machine. Reinforcement in this boring is done after laying the concrete. The cover is fixed on the reinforcement to keep it in the proper position of reinforcement.
If the casing pipe is kept inside during pile foundation concreting, it is known as a cased cast in situ pile. Similarly, if casing pipe is taken out during concreting of pile foundation it is known as uncased cast in situ pile.
A. Cased Cast in Situ Piles
The types of the cased cast in situ pile are as follows:
1. Mac Arthur Piles
The MacArthur pile foundation is made of corrugated steel of uniform diameter throughout the length. Which is inserted into the ground with the core as shown.
When the desired depth is reached the core is pulled back out and then lowered into the corrugated steel shell casing. The concrete is then placed in a corrugated steel tube.
The pile foundation is casting on the site through the above process.
2. Reymond Pile Foundation
In Raymond pile foundation the top is kept 40 to 60 cm in diameter and the bottom 20 to 30 cm. This type of pile foundation is kept closed at the bottom.
3. Button Bottom Piles
These types of pile foundations are used where the final bearing area needs to be increased. This type of pile foundation uses a button-shaped concrete plug.
The use of such piles up to a depth of 23 m is appropriate. This type of pile foundation is capable of transferring loads up to 50 tons.
4. Bsp Base Driven Piles
A helically welded shell of steel plate is used as this type of pile foundation. In this type of pile foundation, a concrete plug is provided at the bottom of the shell.
5. Swage Piles
Sewage piles foundation is used by diving into some soils. This type of pile foundation is specially designed for water.
B. Uncased cast in situ Piles
In this type of pile foundation, the casing pipe is taken out as the concrete work is completed.
Since this pile is formed without casing pipe, it is called uncased cast in situ pile.
The following are some types of uncased cast in situ pile.
1. Simplex Piles
Simplex piles can be easily driven into soft or hard soil. This type of pile has a cast iron shoe at the bottom of the pile. Which can be easily driven into the soil to the desired depth.
The bottom of the pipe is loosened by opening the shoe. The cage of reinforcement is then lowered into it. The pipe is then slowly compacted rather than compacted.
2. Franki Piles
In this type of pile foundation, a concrete plug is made at the front end of the casing pipe.
The Frankie Piles foundation can be used as a high-capacity deep foundation. Which can be used without the need for excavation or dewatering.
3. Vibro Piles
This type of pile foundation has an iron shoe attached to the front end of the steel tube. Which is lowered into the ground with casing pipe to a specified depth. The pile is then formed by withdrawing the steel tube during the concrete.
Vibro piles are kept in sizes of 45 and 50 cm in diameter for loads of 60 to 70 tons. This type of pile foundation can be made in lengths of 25 meters and above.
4. Pedestal Piles
In this type of pile foundation, the casing pipe with the core is lowered into the ground to the desired depth. The core is then pulled out. And are made of concrete. The pressure is exerted by re-inserting the core before the concrete is set. The casing pipe is then gradually removed during the concrete.
3. Timber Piles
The timber pile is placed at a strong level below the water level. This type of pile foundation lasts for about 30 years. This type of pile foundation can be rectangular or round in shape.
This type of pile foundation is kept between 12 and 16 inches in diameter and size. The length of this type of pile foundation is 20 times its width.
This type of pile foundation is usually used for a capacity of 15 to 20 tons. The strength of this pile can be increased by bolting the fish plates next to the piles.
4. Steel Piles
Steel pile is filled with concrete in I-section or hollow pipe. This type of pile foundation can range in size from 10 inches to 24 inches in diameter and the thickness of steel in a steel pile foundation is usually 1 inch.
Due to the small sectional area in the ground is driven easily by machine. This type of pile foundation is commonly used as end-bearing piles.