Learn Everything About Mini Piling Technique
Foundations- The most important step in the construction
Building any infrastructure requires a series of important steps. All of which requires meticulous planning and execution. The first step in construction is always site analysis which includes several mini-steps, each of immense significance.
One of these is soil analysis. It may sound like it is nothing serious but soil quality decides what type of foundation is suitable for a particular infrastructure. In a way, it influences the safety and the lifespan of the structure being built on it.
So how does soil quality decide what type and size of a foundation should be suitable? Soil analysis is typically carried out by Geotechnical engineers.
They calculate the Load-bearing value (LBV) of the soil and analyse soil quality ( moisture content and response to climatic changes ).
The presence of trees in the surrounding and adjacent structures also influences the decision in selecting the right foundations. If you have a construction site in Essex which has restricted site access, then Piling Essex can help you overcome this challenge.
Basic types of foundations
There are numerous types of foundations which are used to support superstructures but most of them fall into one out of two categories: shallow foundations and deep foundations. Where soil quality and LBV of the top soil layer are adequate for construction, shallow foundations are used.
Deep foundations are used when engineers have to dig deep for revealing soil layers of better quality because the surface soil does not have an adequate LBV or quality.
Piling and mini piling- Deep foundations that are highly effective
Piling is a technique that falls in the category of deep foundations. Columnar elements constructed from reinforced concrete and steel are used for piling. Historically, timber was also used but nowadays steel and concrete are preferred.
A foundation may be considered as piled if it is three times deeper than its breadth. Pile foundations transfer the superstructure’s loads through low-quality, weak, or compressible strata to less compressible, stiffer, and stronger, layers of rock or soil. They are highly useful for large superstructures or when the soil is highly unsuitable. They can even be used in water.
Mini piling is a type of piling and is used when the construction site has limited space, making movement and construction difficult especially if the project is large and involves heavy machinery/vehicles. It is also highly suitable for working inside buildings with low headroom.
Mini piles are often used in place of traditional foundations for building new factories and homes in areas where ground conditions are not favourable. They can even be used to reinforce existing infrastructures such as floor slabs, retaining walls, and bridges.
Methods used for mini piling
Sectional Flight Auger (SFA)
When there is very low headroom or the site access is highly restricted SFA or Sectional Flight Auger piling is the preferred method. Hollow stem continuous flight augers are used in sectional lengths to form a pile. This is also useful when the ground has a high water table.
If it is possible to carry out open boring at a construction site, the prefered piling method is augered piling. It is typically used when the ground soil is highly cohesive. Segmental augers following a rotational movement are driven into the ground while the soil flies to the surface.
Temporary casings may be used along with augers for boring if the ground is highly unstable. After achieving the required pile length, steel reinforcements are placed and concrete/grout is used to fill the pile bore This method is highly cost-effective and time-efficient.
Mini Bottom-Driven Piling
This method suits most site conditions. Closed-ended highly thin-walled steel tubes are driven in lengths of 2 to 6m with the help of an internal drop hammer on dry concrete plugs.
The steel tubes are connected by a non-structural fillet weld during the installation till the piles are driven to the required length. The tubes are then filled with concrete (high slump) or grout and a single cage or bar is inserted.
What are the advantages of using mini piling?
- Highly effective in ground conditions with compression and tension.
- Relatively faster installation than other methods.
- An effective technique for creating extensions for homes when the space is tight.
- Mini piling does not affect the adjacent structure and causes minimal vibration/disturbance/vibration during installation.
- High load-bearing capacities can be installed without a substantial increase in cost.
- Greater depths can be reached with relative ease.
- Existing foundations can be reinforced using the mini piling technique.
- Highly suitable for sensitive environments.
- Less steel and concrete are required when Mini Piling is used.