When it comes to pile foundation construction, the selection of the right pile type can affect the success and longevity of a project. Two of the more widely adopted pile foundation solutions are the bored pile and the driven pile. While both essentially provide support according to the same principles for building structures, their installation methods, material demands, and general applicability vary considerably.
We will explore the differences and advantages, and disadvantages between the two methods so informed decisions can be made for any future construction project.
What are Bored Tiles?
Bored piles, or drilled shafts, are a type of deep foundation formed by drilling a hole into the earth and then filling it with concrete, normally with steel reinforcement. They are usually used in soft or loose soil, where other pile types may not be feasible. Bored piles are preferred for congested sites, city areas, or those readily subjected to high groundwater levels. The bored pile construction is non-destructive and can be used where vibration or noise must be kept to a minimum.
What are Driven Piles?
Driven piles are pre-manufactured piles-mostly made of concrete, steel, or timber-driven into the ground by pile-driving machinery. These piles are put into position by striking with a hammer from above, displacing the surrounding soil. Driven piles are used in situations where soils are dense or compact or where the soil medium consists of hard rock, thus providing them with a very high bearing capacity. They are quick and effective to install, but cause huge vibrations and noise.
Key Difference Between Bored Piles and Driven Piles
Materials Used
Bored piles are cast-in-situ concrete piles, that are made using reinforced concrete, or polymer slurry and steel tubes.
On the other hand, driven Piles are made of preformed materials having a pre-determined shape and size. These piles are made of either timber, steel or precast concrete.
Equipment
- Bored Piles:
- Drilling rigs are used to drill a hole into the ground in various soil conditions.
- Augers are used for drilling into the ground and removing the soil from the hole.
- Reinforcement Steel Cage is lowered into the drilled hole for added strength before the concrete is poured.
- A Concrete Pump is used to pump concrete into the drilled hole to form the pile.
- Grout Pumps are used to inject grout into the soil, to stabilize the ground before installation.
- Driven Piles:
- Pile Driving Machine is the primary driving equipment that operates by repeatedly driving piles using a hammer.
- Pile Hammer, either a vibratory or hydraulic hammer is attached to the pile driving machine, which delivers the force to drive the pile into the ground.
- A crane is used to position the piles in place and assist in driving them into the ground.
Advantages
| Bored Piles | Driven Piles |
| Few Disruptions: Quiet installation with less noise and vibration, suitable for urban environments or sensitive locations. Adaptability: Cast on-site in different soil conditions, at various depths, and accommodating different load-bearing requirements. Soft Loose Soil Properties: Excellent for sites characterized by compressible and unstable soils, which fail with most other types of piles. Better for High Water Table Sites: The process does not disturb the groundwater, which makes bored piles best in the high-water table areas. Stable Foundational Base: It provides a stable foundation for having different structures, where challenging soil conditions exist. Best for Congested Areas: Bored piles are more suitable for urban areas lacking much headroom or having narrow access. | Faster Installation: Pre-manufactured piles can be quickly driven into the ground, thus reducing site construction time. High Bearing Capacity: Driven piles compact the surrounding soil, thereby increasing the load-bearing capacity. Cost-Effectiveness: Quick installation and prefabrication reduce labor and material costs. Well-suited to Dense Soil: A snug fit in tightly packed soils or even in hard rock formations. Good Lateral Resistance: Lateral forces are resisted well, making them suitable for structures subjected to winds, waves, and other lateral loads. No Need for Reinforcement Cage: No need for additional reinforcement cage in the construction of driven piles. |
Disadvantages
| Bored Piles | Driven Piles |
| Installation takes more time: The processes of drilling, inserting a steel cage, and pouring concrete take longer than those for driven piles. Costs are higher: Bored piles are costlier because they call for specific types of machinery and highly skilled labor. Soil disturbance: The drilling process, while not as loud or disturbing as the driven pile, does loosen the surrounding soil and can potentially have an adverse effect on nearby structures. Complex equipment: The necessity of drilling rigs, concrete pumps, and other machinery increases the complexity and the resource consumption of the process. Limits in very hard soilsBored piles may not be applicable in very hard or rocky ground unless pre-drilling is done. | Noise-and-Vibration: With the hammering method, loud noise and vibrations would trigger disturbance to people and structures near them, thus affecting the environment, especially in urban areas. Damaged PilesThere is also a possibility that piles, especially timber piles, could get damaged during driving, which would affect their performance. Unsuitable In Soft SoilsDriven piles become ineffective in soft–even loose–soil, and pre-drilling will have to be done, resulting in more time and cost. Depth Piling LimitsCertain softer or unstable soils may not allow a driven pile to reach the desired depth without additional equipment or effort. |
Installation Process
The installation process of the bored pile involves drilling a hole in the ground to the required depth. Once the hole is drilled, a steel reinforcement cage may be lowered into the hole for added strength, and concrete is poured on top to form the pile. However, the entire process is slower than that of driven piles due to drilling and pouring concrete being somewhat complicated.
Driven piles are installed using a pile-driving machine that hammers the piles to drive them down into the ground. The installation system consists of repeatedly striking off the top of the pile to drive it downwards through the soil. This is faster than boring, as the pre-manufactured piles are already ready to be placed into the ground. But, the hammering causes noise and vibration, which can be highly undesirable in many places.
Cost Comparison
Driven piles are generally cheaper than bored piles, considering that they are faster in installation, require fewer resources, and most standard materials are used, especially on simpler sites. This cost difference does not hold in more complicated sites. Although bored piles are costlier and time-consuming to install, they may still be considered in certain situations of soil conditions or when noise and vibration need to be kept under control.
Estimated Costs (in INR):
- Driven Piles: ₹3500 to ₹11000 per linear foot.
- Bored Piles: ₹11000 to ₹22000 per linear foot.
Which One is the Best?
The bored and driven piles options largely depend on the conditions of your construction site. In hard and dense conditions, driven piles work best since they are quick and have high bearing capacity. On the other hand, if the site is extremely noise-sensitive or in soft or loose soils, even with high groundwater levels, bored piles would likely be the best solution.
Conclusion
To sum up, the bored and driven have their pros and cons, depending on its project’s needs. Bored piles do well in hard soil and urban areas. Whereas driven piles are best used where the soil is denser, as they can be used faster and more cost-efficiently. Hence, knowing the differences between the two would help the right pile be chosen for the project. Brick and Bolt’s expert consulting would give you the best option to use for your specific site and needs.