DYNAJET at Ground Zero in New York

As part of the redevelopment of Ground Zero in Manhattan, protruding and very hard concrete was removed using DYNAJET ultrahigh-pressure technology

New York, USA. More than six years after 9/11, the US version of the DYNAJET UHP 170 was delivered for a large-scale operation at the Ground Zero construction site in the centre of New York City.

The ultrahigh-pressure unit, operating at 2,800 bar (40,600 PSI) with a water volume of 18 l/min (4.76 USgal/min), was selected to remove protruding and very hard 984 kg/m² concrete from the foundations and pillar construction of the new building. During concrete filling work, some concrete had accidentally come into contact with the reinforcements which, at this stage, should not yet have been filled. So that the traction between the reinforcements and the concrete was not endangered later, up to 15 cm of the extremely hard and resistant concrete had to removed from the foundations without damaging the reinforcements.

Where chisels or pneumatic hammers failed, the DYNAJET unit was able to carry out this task without problem. What is more, due to the central lifting eye and the smallest footprint in its class, the US version of the DYNAJET UHP 170 could also be positioned as near as possible to the place of application.

When water is used for work of this kind, no vibrations or micro-cracks develop. The deployment of mechanical tools, such as pneumatic hammers or similar, is not permitted owing to the risk of vibrations.
A 2,800-bar (40,600-PSI) round-jet nozzle was deployed to cut and break away the concrete. The water jet has a destructive effect on the concrete in three respects: direct pressure, cavitation, and pressure regulation of micro- and macro-cracks.

In the first three weeks, the unit had already achieved more than 270 hours of operation without problem.
Reliable, powerful and state-of-the-art concrete removal => that’s the DYNAJET way!