Cased piles are a type of foundation element that consists of a shell surrounding it. These piles are typically cast on-site, and are known as cased cast-in-situ concrete piles. The shell of these piles is usually constructed using steel. One of the advantages of using cased cast-in-situ concrete piles is that they are suitable for use in any type of soil.
Cased cast-in-situ concrete piles are a popular choice for foundation elements due to their versatility. The use of steel for the shell of these piles makes them strong and durable. Additionally, the fact that they can be cast in situ means that they can be easily customized to suit the specific needs of a construction project. This makes them a great option for a wide variety of applications, from residential homes to large-scale commercial buildings. Overall, cased cast-in-situ concrete piles are a reliable and effective foundation solution for any type of soil.
Advantages of Cased Cast-in-Situ Concrete Piles
Cased cast in situ piles offer several advantages in their construction and inspection. Firstly, the shell of the pile provides driving resistance, making it easier to drive the pile into the ground. Secondly, during the process of filling the shell with concrete, the concrete is not disturbed, ensuring its integrity and strength.
Additionally, the internal inspection of the pile can be carried out after the driving of the shell, allowing for a thorough check of the pile’s quality and structural integrity. Finally, in the case of cased piles, they can be easily cut or extended if required, providing flexibility in construction and allowing for adjustments to be made as necessary.
Types of Cased Cast-in-Situ Concrete Piles and Uses
Different types of cased cast in situ concrete piles are:
- Raymond piles
- Mac-Arthur piles
- Union metal monotube pile
- Swage pile
- Western button bottom pile
Raymond Piles
Raymond piles were first introduced in 1897 by A.A. Raymond and are considered an economical option for cast in situ piles. There are two variations of Raymond piles: the Standard Raymond pile and the Step Taper Raymond pile. Both types are cast in place, meaning they are created on-site, rather than being prefabricated and transported to the location. The Standard Raymond pile and Step Taper Raymond pile differ in their design, with the Step Taper Raymond pile having a tapered shape that allows for greater load-bearing capacity. Despite their age, Raymond piles remain a popular choice for foundation construction due to their cost-effectiveness and reliability.
Standard Raymond Pile
The Raymond pile is a type of friction pile that is characterized by its heavy taper of 1 in 30. Its diameter gradually decreases from the top to the bottom, with a diameter of 40 to 60 cm at the top and 20 to 30 cm at the bottom. The length of the pile can range from 6 to 12 meters.
To reinforce the Raymond pile, it contains a corrugated steel shell that is closed at the bottom and is reinforced with wire. The wire is wound spirally around the shell with an 8 cm pitch. The shell is driven into the ground using a core or mandrel. Once the pile has reached the required depth, the mandrel is removed and the pile is filled with concrete.
The heavy taper of the Raymond pile makes it ideal for use as a friction pile, as the taper allows the pile to develop significant frictional resistance against the surrounding soil. Additionally, the use of a corrugated steel shell and concrete filling provides additional reinforcement and stability to the pile, making it a reliable foundation option for various construction projects.
Step Taper Raymond Pile
The step taper Raymond pile is a type of pile that is constructed using a series of shells that are stacked on top of each other. However, each shell has a different size, with the shell size gradually increasing from the bottom to the top. To facilitate the driving process, the bottom shell is made of a heavier gauge and is closed at the bottom. The next shell section is then placed on top of it, and the connection between the steel shells is made using screw connections.
Typically, a 2.5 cm increase in diameter is provided for each shell section with respect to its bottom one. To drive the shell sections, a steel mandrel or core is used. These step taper random piles can be driven up to a depth of 36 m and can be used as both friction piles and end bearing piles.
One of the advantages of the step taper Raymond pile is that it can be easily inspected. Additionally, fresh concrete can be filled into the pile, and it provides length flexibility. Compared to a standard random pile, the step taper Raymond pile has several advantages and can be a useful option for various construction projects.
Mac Arthur Piles
Mac Arthur piles have a uniform diameter and their shell is constructed using corrugated steel. The driving process involves utilizing a heavy gauge steel casing that encompasses the core. Once the pile is driven to the desired depth, the core is removed and a corrugated steel shell is inserted into the heavy gauge steel casing. This shell is then filled with concrete, and the outer hard casing is removed.
Union Metal Monotube Pile
Union metal monotube piles are a type of pile that does not have a mandrel, only a shell made of tapered fluted steel. These piles are suitable for a wide range of soil conditions, including those that require end bearing and friction load carrying capacity. Due to their rigidity and watertight construction, these piles can be driven to greater depths using a hammer. Once the pile is driven, it is inspected before being filled with concrete to complete the foundation.
Swage Pile
Swage piles are a popular choice for constructing foundations in hard soils. To drive the pile shell, a pre-cast concrete plug is attached at its bottom. A steel core is then inserted into the shell and driven into the ground. The shell is swaged out by the taper of the plug to form a water-tight joint.
Once the desired depth is reached, the core is removed and the shell is filled with concrete. This process ensures a sturdy foundation, as the concrete fills any voids or gaps created during the driving process. Overall, swage piles are a reliable solution for constructing structures on challenging terrain.
Western Button Bottom Pile
Western button-bottom piles are a popular choice for construction in end-bearing soils. These piles are designed with a concrete button at their base, which serves to help the pile penetrate into the ground. The button is wider than the rest of the pile, measuring approximately 25 mm in diameter, and has a sharp bottom that aids in creating a larger hole during the driving process.
The design of the concrete button allows for the elimination of side friction, which is the force that resists the movement of the pile along the sides of the hole it is being driven into. By reducing or eliminating side friction, the pile can be driven more easily into the ground, resulting in a more stable foundation.
Overall, the use of Western button-bottom piles can help ensure that a structure is built on a solid foundation. By taking advantage of the benefits provided by the concrete button at the base of the pile, these types of piles are an effective way to create stable foundations in end-bearing soils.
A steel pipe with a 12mm thick wall is used to drive a combination of the pipe and a concrete button into the ground. The goal is to reach a desired depth. Once this depth is achieved, a corrugated steel shell is placed into the steel pipe. The shell is made of a steel plate that is welded at the bottom, and this plate is attached to the concrete button using a long socket wrench. After this step, the steel casing is removed and the shell is filled with concrete. This method of pile construction is suitable for loads of up to 50 tons and can be used for depths of up to 23m.