Use of a vacuum excavator to create accurate pile lengths on High Speed 2 (HS2) could cut costs, reduce risks and improve sustainability for the wider industry, according to HS2 contracting joint venture SCS.
SCS, which is formed from Skanska, Costain and Strabag, is using the innovative approach to remove excess concrete from the top of the pile length while still wet rather than using the conventional approach of breaking down the pile once the concrete is cured.
The “zero trim pile technique” involves sucking out excess concrete while still wet
HS2 Ltd has said that the technique could have benefits for the wider construction industry and is better for the environment, safer for workers and reduces construction noise.
SCS site superintendent Lee Piper identified the opportunity to test the technique on HS2 and worked with Cementation Skanska project director Deon Louw to develop the solution with Hercules Site Services for use of HS2’s Euston approaches site.
The “zero trim pile technique” involves sucking out excess concrete while still wet using a new vacuum excavator technique. Traditionally in piling, concrete is overpoured and then workers have to break out the excess concrete. This can cause a lot of health problems, including hand-arm vibration syndrome, hearing loss and silicosis. By removing the need to break out excess concrete, this new approach is safer for workers, and also reduces the manhours involved in complex piling work.
According to HS2 Ltd client director Malcolm Codling, it is estimated that use of the technique will save 60,000 hours of work at Euston.
Although use of vacuum excavation in construction is not a new solution, the use for piling applications represents a novel use of the equipment and has proved successful so far. HS2 Ltd has said that the extracted concrete is being retained on site and reused elsewhere in the construction.
Piper said: “I have worked in the construction sector for over 20 years, and the same piling techniques have been used throughout that time. Working with colleagues I saw an opportunity to try a new approach and was supported to do so by HS2.
“This technique could be transformational for the construction sector, reducing the health risk that results from breaking piles. The additional benefits of noise reduction, time and carbon savings mean the technique should be attractive for the whole sector to use going forward.”
Louw added: “We’ll be installing around 2,000 piles over the next three years in the Euston area. This zero trim innovation will bring amazing benefits in terms of reduced carbon, noise reduction and safer ways of working for our site teams. The potential health impacts associated with concrete breakdown are well known, so to be able to mitigate these risks from the outset is great for our people.
“Longer-term, we’ll be looking to see how we can use this innovation on future projects. It really does have the potential to be a game-changer for our industry.”
Department of Civil Engineering: https://www.ibu.edu.ba/department-of-civil-engineering/