Marr Contracting had its M2480D heavy lift luffing (HLL) tower crane mobilised at the Hinkley Point C power plant project in the UK, assisting with the handling of tunnel boring machines.
Hinkley Point C nuclear power station (HPC), being built by EDF (UK), is one of Europe’s largest and most complex construction projects and the first new nuclear power station to be built in the UK in more than 30 years. In 2017 Balfour Beatty was awarded the contract to deliver the tunnelling and marine works as one of three major packages of works the contractor is delivering on Hinkley Point C.
Marr Contracting was one of the companies selected to provide cranage solutions at the project. Tom Batley, a director at Marr, said this was the company’s first project in the UK. Balfour Beatty’s scope of works was for the construction of the outtake and intake tunnels for the cooling water needed for the nuclear reactor units 1 and 2. It involved installing the tunnel boring machines (TBMs) and associated tunnel segments, along with conveyer systems used for the removal of spoil during tunnel excavation works.
Balfour Beatty sought an alternative to the traditional approach of using large crawler cranes and a gantry system for handling. This would have required a lot of temporary works and double handling of equipment for the tunnel construction and ring segments for the tunnel lining. Instead, Marr was contracted to position one of its M2480D heavy lift luffing (HLL) tower cranes in a location where it could offer a single solution for all the lifting requirements.
Placing the M2480D on 72 m of free-standing tower with a 102 m radius boom and fly combination allowed independent operations above the other cranes onsite, reducing the potential for boom clash on the project. Moreover, the freestanding crane occupied significantly less area than a crawler, helping to alleviate logistical complexity on the busy construction site.
With a capacity of 25 tonnes at 100 m radius and a maximum lift capacity of 220 tonnes in this configuration, the solution provided the lifting capability required to pick materials and components from the tunnel segment storage area and lower them to the pit bottom in one lift. The M2480D’s lift capacity and dual hook configuration also gave Balfour Beatty the ability to install the TBM with one crane and unlike a heavy lift crawler option, the M2480D required no super lift attachment to complete any of its lifts, said Marr.
Moreover, the coastal location of the jobsite presents a constant risk of high winds. Where safe operation in wind speeds above 9 m per second would have been largely unachievable for mobile and crawler cranes, the M2480D allowed operational lifts in conditions of up to 20 m per second where the dynamics of the load allowed, said Marr.
The installation of the TBM also presented the challenge of how to lift and rotate a number of heavy components from transport to installation on the project, without using two separate cranes to rotate the loads. Compounding this complexity, a number of tower cranes were already working on the project for other contractors.
“Early engagement between Balfour Beatty and Marr enabled a safe and suitable foundation to be designed for this geotechnically complex location. The two stand out benefits of the crane were flexibility and dual hook ability. The boom length and very high lift capacity enabled tunnel operations to be flexible to the changing site configuration, allowing us to pick and place all plant, equipment and materials over a very large area of the site. Secondly, the dual hook lift ability enabled the crane to single-handedly pick and rotate heavy TBM components with ease, without the need for a second crane. A very impressive and versatile crane – it was great to have the opportunity to work with it!” said Patrick Brady, temporary works manager, HPC tunnels and m marine contract, Balfour Beatty Major Projects.
