Running a construction site in a busy urban environment is always a challenge, but constructing a 30-metre-deep basement in the middle of one is even harder. Traditional excavation requires space; long-reach excavators can span up to ten metres when fully extended and heaped earth further reduces the limited operational space.
When working on jobs like St Giles, a mixed-use development that includes a four-storey basement that runs directly over London Underground’s Northern Line and the future site of Crossrail, Carey Group teams simply don’t have the space required to undertake traditional excavation.
To overcome this, we deploy one of our two specialist telescopic excavators, Hector and Heidi. These ZX-series Hitachi excavators are specially designed to boost productivity when undertaking deep excavations. The excavators can safely extract earth from depths of up to 25 metres, fully retracting their bucket in a matter of seconds before depositing it into a waiting dumper truck.
“These machines have proven to be a great investment for our site teams,” says Gary Condon, Managing Director of Careys Plant & Fleet. “In addition to their relatively small footprint, they also include sliding cabs with viewing plates in the footwells to enable the operator to get better visibility of what they’re excavating”.
The machines also include a range of useful safety features, including working lights to enable the operative to work in low light conditions, CCTV at the head of the arm and a twin rope system which holds the telescopic arm in place in the event of one rope breaking.
“Previously, we had to use long-reach excavators to fill a skip and then crane it out of deep excavations, but these machines enable us to do the same job in a fraction of the time, more safely and with far greater precision. They’re also extremely reliable, which is a huge benefit to our project teams, as on tight programmes, you can’t afford to lose half a day if a key piece of equipment fails.”
“When Careys first bought these machines in 2010 we were the very first in the country to do so,” continues Gary, “We were working on the British Museum, and simply didn’t have the space to undertake a traditional excavation methodology. By going out to the market and looking at different solution, we were able to develop a programme that was quicker and far more effective for our client.”.