Dutch foundation contractor Voorbij Funderingstechniek’s Voton HSP (or High Speed Pile) is a displacement cast in place concrete pile that makes clever use of the company’s expertise in sheet piling installation.
Piles of up to 17m can be installed in a couple of minutes with virtually no noise or vibration, says the company.
Voorbij developed the system in 2001 and has already installed nearly a million linear metres of HSP pile in the Netherlands. Applications to date have mostly been in the construction and building sectors, but the company has just completed foundations for a piled embankment on the Rotterdam-Barendrecht tram system.
This is the first use of the system in an infrastructure project, and is arguably the application that makes best use of its benefits.
HSP piles are installed using modified crane-mounted sheet piling equipment, which installs a closed-end steel casing primarily by hydraulic pull-down. The rig can also apply a vibrational force to assist installation and retrieval of the casings; and in extreme cases water jetting can help penetration through stiff clays.
With the steel casing in place, high slump concrete is pumped through the centre of the casing, which causes a pneumatic pinch valve just above its base to open when a predetermined concrete pressure is reached. This ensures the concrete is dense and compact and that there is no chance of the shaft collapsing as the casing is withdrawn.