Allerton Waste Recovery Park next to the A1(M) motorway near Knaresborough in North Yorkshire, UK, processes 320,000t of waste a year from the surrounding area using a mix of mechanical treatment, anaerobic digestion and incineration. Nearly all but the process plant for the project, which started operating in early 2018, were procured using NEC.
In 2014 North Yorkshire County Council appointed Amey, Equitix and Pensions Infrastructure Platform to deliver and then operate the facility for 25 years. Amey contracted the general building and civil engineering works to Vinci Construction UK under a £55 million NEC3 Engineering and Construction Contract (ECC) Option A (priced contract with activity schedule).
The works included design and construction of the tipping hall, mechanical treatment building and bunker, anaerobic digester foundations, amenity building, substation, weighbridges, access roads, carparks and landscaping. A total of 60,000m3 of material was excavated and re-used on site for landscaping and engineering backfill.
Amey construction director Mark James says NEC was felt to be the most appropriate contract suite for the complex package of building and civil engineering works supporting the waste recovery plant.
‘The use of an ECC Option A lump-sum contract also meant the administration of the contract was very straightforward. Both parties are experienced NEC users so we understood the various NEC risk-management and change-management processes and used them to good effect.
‘Risk and change was proactively managed as the contract progressed, supported by NEC mechanisms such as early warnings and compensation events. Overall we worked very much in accordance with the ‘spirit of mutual trust and co-operation’ set out in the contract, enabling us to work more efficiently and achieve a successful outcome.’
Vinci Construction project manager Rob Henderson says construction of the 30m high waterproof mechanical treatment bunker in the tipping hall, which extends 9m below ground level, required particularly close collaboration with the adjacent energy-from-waste (EfW) project.
‘Examples included using sheet piling to support the bunker excavations to enable the adjoining EfW foundations to be constructed in parallel. In addition, 90% of wall reinforcement was prefabricated on the ground to decrease bunker construction time.
‘We used thermo-couples in the bunker wall concrete pours to determine early strength gain for faster shutter striking but at the same time avoiding cracking. We also changed the original design for the inclined bunker tipping chutes from being directly formed against backfill to box structures, allowing the bunker walls to progress ahead of backfilling.’
‘Finally, due to it being both a construction and process engineering project, all construction sequences had to be carefully planned and monitored to manage safely and effectively the 650 personnel and up to 12 cranes on site. Collaborative planning sessions were organised and daily coordination meetings were held with all companies on site.’
Benefits of Using NEC
- NEC contracts are ideally suited to delivering complex projects involving a wide-range of integrated building and civil engineering works.
- NEC’s comprehensive risk-management and change-management processes enabled the project to be safely delivered on time and on budget.
- NEC requirement work in a ‘spirit of mutual trust and co-operation’ helped to ensure collaborative working on site, particularly at the numerous interfaces between the construction and process parts of the works.