PROXIMITY AND RISK GO HAND-IN-HAND WHEN PILING!

In piling – the closer you get to something – the more likely you will be of damaging it. Whether through vibration, collapsing bores, or lateral ground displacement – it’s always better to be further away to reduce the risk.

However, choosing the right piling methodology is therefore of paramount importance when working near assets or utilities (pipes, services ducts, etc.) - because sometimes, well, you just have to put a pile "very" close.

Screw piles are often a foundation methodology of choice in these situations for the sole reason that they can be installed very close to existing utilities or plant/assets with a reduced risk of damaging it.

An example of this was recently encountered by our Revex Piling site team, who were installing screw piles with a 700mm diameter helix to depths of 36m to take a load of 1,364 kN (compression, ULS). However, near ground level the larger helix (well, larger than normal) was close to a manhole, with entry/exit pipelines. While the new drainage system was designed with a minimum proximity of 1m in mind, the existing drainage that was to remain was within the intended tolerance.

Congrats to the site team, who took all of the standard and sensible precautions:
- The drawings were checked.
* Indeed, the pile and the manhole were close to the marked pile position.
- The dimensions the existing SWMH deviated by 300mm (300mm closer!) and a Request for Information (RFI) was raised with the Contractor and Structural Engineer and Screw Pile Designer.
- Condition of the manhole was checked.
- Location of pipelines were marked on the ground.
- Agreement was made that piling could proceed.

Know your Methodology: It's key to ensuring you minimise risk onsite - whether through $$$, programme delays, or quality issues.