Hawks crawler cranes on UK tunnel project
By Alex Dahm14 July 2022
Rental specialist Hawks Crane Hire supplied four Kobelco crawler cranes for a road tunnel project in the UK.
The lattice boom crawler cranes are a pair of 250 tonne capacity CKE2500-G s and two 100 tonne CKE900G-3s. First of the four to be delivered was one of the smaller models, in January 2021, while the final unit, the second 250 tonner, was delivered in June 2022.
They are working on Transport for London’s £1 billion (US$1.18 billion) Silvertown Tunnel project. A new 1.4 km twin-bore road tunnel will link Silvertown with the Greenwich Peninsula in east London. It is the first tunnel under the river Thames in more than 30 years. Main contractors are Bam Nuttall with sister company Wayss & Freytag Ingenieurbau, Ferrovial Agroman and SK E&C.
Both CKE2500G-2s were delivered with 48 metre booms, one with a 100 tonne hook block and the other a 70 tonne block. Capacity at a 15 metre radius is 50.5 tonnes.
Site restrictions meant there were operational challenges to deal with, according to Elliot Hawkins, Hawks Crane Hire sales director, “The main boom for both machines had to stay under the overhead Emirates cable car, which runs across the site, and also had to be slew restricted due to the adjacent Docklands Light Railway (DLR) lines running parallel with the site, with Kobelco’s slew restrictors coming in very handy during operations.”
Working around the three main shafts, both CKE2500G-2s were used to remove spoil from the shafts. The smaller cranes, with their 36.6 metre booms, were used by piling contractor Keltbray on the tunnel boring machine launch chamber.
“Both CKE900G-3s worked as ‘tailing cranes’”, said Hawkins, “lifting the tailing end of the tilt bed, with a maximum weight of 24-tonnes, where the T-shaped rebar cages were spliced together to make the 102 tonne, 32 metre long counterfort piles, which were filled with more than 500 cubic metres of ‘low-carbon’ concrete once in position.”
Environmental concerns also played a part in choosing the Kobelco crawler cranes for the works, according to Hawkins, with its KCross remote operation management system, which is designed to help maximise machine efficiency and uptime, key to the decision making.
“Our client was especially interested in gathering as much information as possible on all four cranes’ diesel usage and emissions whilst they were on site, particularly as it was keen to reduce emissions as much as possible on site. It even ran a competition between the contractors to see how much money it could save while reducing fuel consumption.
“More importantly,” added Hawkins, “the information was not only useful during the project but will be used as part of its wider research into how emissions and fuel usage can be reduced on future projects.”