Contiguous piling is a foundational technique in civil engineering, widely employed in the construction of heavy and tall structures such as buildings and bridges. This method involves the installation of closely spaced piles to form continuous barriers or retaining walls, providing essential support and stability in various construction scenarios.
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What is Contiguous Piling?
Contiguous piling is a deep foundation technique that involves the installation of closely spaced reinforced concrete piles to create a continuous retaining wall. These piles are constructed by drilling into the ground and filling the boreholes with concrete, normaly reinforced with steel cages. The gaps between adjacent piles are small, typically ranging from 50 to 150 mm, allowing some soil retention while providing structural support.
The main advantage of contiguous piling is that it offers effective lateral support while minimizing excavation-related disruptions. Unlike secant or tangent pile walls, which create a watertight barrier, contiguous piling allows some groundwater seepage, making it suitable for dry or semi-dry soil conditions.
Applications of Contiguous Piling
Contiguous piling is widely used in various construction scenarios, including:
1. Deep Excavations: This method is frequently used to create retaining walls for deep excavations, such as basements, underground parking facilities, and metro stations. The piles support the surrounding soil, preventing collapse and reducing the risk of ground movement.
2. Bridge Foundations: For bridges and other heavy infrastructure projects, contiguous piling provides a stable foundation that can withstand significant loads. It is particularly useful in areas with soft or unstable soil conditions.
3. Slope Stabilization: Contiguous piling is often employed to stabilize slopes and prevent landslides. By acting as a retaining structure, it reinforces the natural terrain and mitigates the risk of soil movement.
4. Highway and Railway Infrastructure:Many road and railway projects require the construction of retaining walls to support embankments or cuttings. Contiguous piling ensures the stability of these structures while allowing construction to proceed efficiently.
How is Contiguous Piling Processed?
The contiguous piling process involves several key steps:
1. Site Investigation and Design
Before piling begins, a thorough site investigation is conducted to assess soil conditions, groundwater levels, and load-bearing capacity. Engineers use this data to determine the optimal pile spacing, diameter, and depth.
2. Drilling and Boring
A rotary or continuous flight auger drill is used to bore holes into the ground at specified intervals. The depth and diameter of the piles depend on the project’s structural requirements.
3. Reinforcement Placement
Steel reinforcement cages are inserted into the boreholes to enhance the structural integrity of the piles. This reinforcement helps resist bending and shear forces.
4. Concrete Pouring
Concrete is poured into the boreholes, either through tremie pipes or direct placement. The quality of the concrete is carefully monitored to ensure a durable and stable pile structure.
5. Curing and Strength Testing
Once the concrete has been poured, it is left to cure for a specified period. Engineers conduct strength tests to verify the load-bearing capacity of the piles before proceeding with further construction activities.
Advantages of Contiguous Piling
Cost-Effective: Compared to other retaining wall systems, contiguous piling is more economical.
Quick Installation: The process is relatively fast, reducing construction timelines.
Minimal Vibration and Noise: Suitable for urban areas where reducing disruption is essential.
Flexible Design: Can be adapted to various soil conditions and construction requirements.
Limitations of Contiguous Piling
Not Completely Watertight: Some groundwater seepage may occur, requiring additional waterproofing measures.
Limited in Very Soft Soils: In extremely soft or loose soil conditions, alternative retaining methods like secant piling may be more suitable.
Requires Skilled Execution: Proper design and installation are crucial to ensure structural integrity.
Pile breaking
Once the contiguous piles are installed, the next critical step is pile breaking or processing. The exposed pile heads must be trimmed to the correct level to ensure proper load transfer to the superstructure. Traditional pile breaking methods often involve labor-intensive and time-consuming techniques such as hydraulic breakers or hand chipping.
A more efficient and advanced approach is the Brextor® pile breaking system. This innovative method provides precise, safe, and efficient pile breaking, reducing construction time and labor costs while maintaining high-quality results.
Pile breaking with Brextor®
Brextor® is an innovative system for pile head processing. This technology enables precise, safe and fast removal of the pile head compared to conventional methods.
With this method, not only single piles, but also all types of pile walls (tangent, secant or contiguous) are processed gently by machine. The work is done by one person and one machine. The weather conditions have no influence here.
Brextor® offers the following advantages:
🏗 Increased construction quality
Perfect pile breaking without cracks in the pile body or spalling on the pile outer skin, no bent or torn reinforcements and a height accuracy of +/- 1cm.
💵 Reduced construction costs
The demolition material consists of 80% gravel 0-30mm and can therefore be reused directly on the construction site. In addition, Brextor® requires less working space than conventional mining methods. This means that not only expenses for transportation and disposal incl. fees are saved, but the purchase and supply of replacement material is also eliminated. Furthermore, the preparatory work eliminates the need for a separating diamand cut at the final extraction level and the cleaning effort is massively lower than with conventional extraction methods.
⏱ Shortened processing time
For example, a pile with a diameter of 1 m and a height of 1 m can be processed within 40 minutes. A daily output of up to 16 piles is possible. In addition, Brextor® provides reliable performance and therefore increased planning security.
♻️ Environmentally friendly
With Brextor®, the demolition material (80% gravel 0-30mm) can be reused directly on the construction site. Brextor® also requires less working space. This saves excavation and replacement material. By reusing the demolition material directly on the construction site and saving on excavation and replacement material, transportation can be saved. In addition, landfills are less polluted.
👷 Increased health & safety at work
No heavy physical labor is required for pile processing, which massively reduces the risk of health hazards such as HAVS syndrome. Brextor® also avoids working in danger zones.
Find out more about Brextor® here:
Contact us for more information and find out how you can benefit from this revolutionary pile breaking method.
Call us on +41 41 495 05 20 or send an e-mail to info@brc.swiss. We look forward to working with you and taking your projects to the next level.