How to choose type of pile foundation?
When it comes to choosing the most suitable type of pile for a given condition, it’s important to consider the advantages and disadvantages of each option. Three common types of pile are driven piles, driven and cast-in-place piles, and bored and cast-in-place piles.
Driven piles are prefabricated piles that are driven into the ground using a pile driver. They can be made from a variety of materials including timber, steel, and concrete. One of the main advantages of driven piles is their ability to be installed quickly and efficiently, making them a popular choice for many construction projects. They are also able to resist high loads and can be installed in a variety of ground conditions. However, one potential disadvantage of driven piles is that they can be noisy and cause vibrations during installation, which can be a concern in urban areas.
Driven and cast-in-place piles combine the benefits of both prefabricated and cast-in-place piles. These piles are first driven into the ground like traditional driven piles, and then the hollow core is filled with concrete, creating a cast-in-place pile. This method allows for faster installation compared to bored and cast-in-place piles, while still providing the benefits of a cast-in-place pile, such as improved load capacity and durability. However, this method may not be suitable for certain ground conditions or situations where noise and vibrations need to be minimized.
Bored and cast-in-place piles are created by drilling a hole into the ground and then filling it with concrete. This method allows for a larger diameter pile to be installed, which can provide greater load capacity. Bored piles can also be installed to deeper depths than other types of piles. However, the installation process can be slower and more expensive than other methods, and the equipment used may require more space on the construction site. Bored and cast-in-place piles are often used in situations where the soil conditions are challenging or where large loads need to be supported.
Fig.1: Selection of types of pile foundations
Driven Pile
To select driven piles for a project, it is important to have knowledge about their applications, advantages, and disadvantages. Driven piles are capable of being installed to considerable depths and are particularly suitable for marine structures. They offer sufficient stability in squeeze ground, are not affected by ground heave during placement of neighboring piles, and allow for examination and inspection of pile material prior to installation. In addition, construction of driven piles is not influenced by groundwater.
However, there are certain disadvantages associated with driven piles. The use of excessive force during installation can cause unobserved damage and possible severe deterioration, leading to an increase in construction schedule and cost. Driven piles cannot be installed in low headroom conditions and end enlargement may not always be beneficial. The driving process can also produce vibrations and noise, which can result in damages. Lastly, driven piles are not cost-effective when the amount of material in the pile is controlled by driving stress instead of permanent load stresses.
Fig.2: Driven Pile Foundation
Driven and Cast-in-Place Pile
Driven cast in place piles are a popular foundation option in construction, and like all building methods, there are pros and cons to consider. One of the advantages of this type of pile is that it allows for the construction of an enlarged base in certain cases. Another advantage is that a closed-end tube is driven into the ground to prevent the effect of ground water. Additionally, noise and vibration can be reduced during the construction process.
Furthermore, the length of the pile can be adjusted based on the level of the bearing stratum, and it is not affected by the stress of driving or handling. However, there are also disadvantages to this method. For example, the length of the pile cannot be altered once it has been installed, and it may experience waisting and necking when used in squeezing ground unless special considerations are made during concreting.
Another disadvantage is that the construction process can cause damage to nearby structures due to the vibrations and noise generated during the process. This method is also not suitable for areas with low headroom, marine structures, or river construction without special adaptations. Additionally, the displacement of the ground during the driving of the pile can result in damage to adjacent green concrete, and once construction is complete, it is not possible to examine the concrete.
Fig.3: Construction of driven and cast in situ pile
Bored and Cast-in-Place Pile
Bored and cast-in-place pile foundation offers numerous advantages, such as the ability to install considerably long piles, even in low headroom situations, and the use of large diameter piles. Additionally, the soil excavated during construction can be inspected, sampled, or tested. The length of bored and cast-in-place piles can be adjusted to suit the ground conditions, and they can be installed with minimal vibration and noise. However, there are also disadvantages to this type of pile foundation. It is susceptible to necking in squeezing ground conditions, and poured concrete can be examined for quality. Enlarged end piles may require special approaches for construction. Furthermore, the presence of artesian water pressure can lead to washing out of cement, and settlement of neighboring buildings may occur if piles sink in cohesionless soil. Grouting may be required to stabilize the base of the pile in sandy or gravelly soil.
Fig.4: Bored and cast in place pile
How to choose type of pile in the same pile category?
When selecting a pile for a construction project, it is important to first determine the appropriate pile category based on the site conditions and requirements. Once the pile category has been established, the next step is to choose the suitable type of pile from among the available options of timber, steel, or concrete piles, depending on the category selected.
For the category of driven piles, there are various types and forms of piles available to choose from. These include timber piles, steel piles, and concrete piles. The appropriate type of pile to select will depend on factors such as the soil conditions, required load capacity, and construction method.
In the category of driven and cast in place piles, the selection of the appropriate type of pile will again depend on site-specific factors such as the soil conditions and required load capacity. The available options include timber piles, steel piles, and concrete piles, and the choice of pile will also depend on the construction method to be used.
For the category of bored and cast in place piles, the selection of the suitable pile type will once again depend on factors such as the soil conditions and required load capacity. The options available in this category include timber piles, steel piles, and concrete piles. The choice of pile will also depend on the specific construction method to be employed.
Selection of Driven Pile
Table-1 provides guidance for selecting the appropriate type of driven pile based on various factors such as their advantages and disadvantages, as well as construction conditions. Driven piles can be constructed from a variety of materials including timber, concrete, and steel.
Choosing the right type of driven pile is crucial in ensuring the stability and safety of any construction project. The table provides a comparison of the advantages and disadvantages of each pile type, which can be used to make an informed decision based on the specific project requirements.
Additionally, the construction conditions must also be taken into consideration when selecting the appropriate driven pile type. This includes factors such as soil conditions, location, and load capacity requirements. By using Table-1 as a guideline, construction professionals can make an informed decision about which type of driven pile is most suitable for their project.
| Types of driven pile | Suitable condition | Unsuitable condition |
| Timber driven pile | Suitable option for temporary works or when the load is small | Cannot be used when loads are large. It may suffer decaying if water level fluctuates, and it is not suitable for heavy driven since it may experience unseen splitting. |
| Concrete driven pile | Extra reinforcement ration is needed to make the pile withstand driven force, it needs time after casting to obtain necessary strength and hence there is a gap between casting and driven, and it may suffer from unseen damage due to driven forces. | Suitable for all loading conditions, it can withstand corrosive soils |
| Steel driven pile | It is suitable for all loading condition, it does not suffer damages due to driven forces, it can be extended and cut down. Considerable long driven pile can be used by welding on additional length. | It is subjected to corrosion in marine condition above soil level and subsequently it needs protection, And long piles may go off the line during driving |
Selection of Driven and Cast-in-Place Pile
Table-2 is a helpful tool for selecting the appropriate type of driven and cast in situ piles, based on their specific advantages, disadvantages, and the construction conditions present. By considering these factors, it becomes easier to identify the most suitable pile type for a particular project.
The advantages and disadvantages of each pile type can provide insights into their respective strengths and weaknesses, which can then be matched against the specific requirements of the project. This helps to ensure that the selected pile type is well-suited to the job at hand, and can deliver optimal results.
In addition to the advantages and disadvantages, the construction conditions present can also influence the choice of pile type. For example, if the project site is located in an area with challenging soil conditions, a particular pile type may be more suitable than others. Similarly, if the site has limited space or accessibility, a different type of pile may need to be chosen.
By carefully considering these factors and utilizing Table-2, it becomes possible to select the most appropriate driven or cast in situ pile type for the project, ensuring that the resulting foundation is strong, stable, and durable.
| Types of driven and cast in place pile | Suitable condition | Unsuitable condition |
| Withdrawable tube driven and cast in place pile | It is cheaper compare with the other type | It is not good option to use in water bearing sand and squeezing soil |
| Un-withdrawable tube driven and cast in place pile | It is suitable option for squeezing soil, water bearing sand, and when the pile needs driven after ground heave. | It is more expensive compare with the other type of pile |
Selection of Bored and Cast-in-Place Pile
A cost-effective option for bored and cast in place pile is the simple uncased mechanically augered pile. This type of pile works well in cohesive soil that ranges from firm to stiff. However, the expense of the pile installation rises if a casing is implemented and removed, along with the usage of a slower boring technique.