Construction starts on £6.3 bn of NEC contracts in Belgium

After two years of enabling works, permanent construction has now started on the €7.5 billion (£6.3 billion) NEC-procured sections of the Oosterweel ring road project in Antwerp Belgium. The two NEC4 Engineering and Construction Contracts (ECC) Option C (target contract with activity schedule) form the right-bank portion of the government’s massive project to close the city’s R1 ring road via a new crossing under the River Scheldt.

Government-owned company Lantis is the client, project manager and supervisor for both NEC contracts. Sections 1 and 2 on the left bank have been procured using traditional lump-sum contracts.

Oosterweel section 3B, which is for 4 km of double-deck tunnels under Antwerp docks and the Albert Canal plus lowering and covering 4 km of the existing ring road, now has a target cost of €6.1 billion (£5.1 billion). This is an 87% increase from mid-2023, making it the largest ECC awarded to date. It is exceeded only by the Hong Kong government’s HK$61.1 billion (£6.2 billion) NEC4 Design Build and Operate Contract (DBOC) for West New Territories landfill extension let in August 2023.

The NEC4 ECC Option C for Oosterweel section 3A, which is for a 2 km long interchange at the northern portal of the new Sheldt tunnel, is now valued at €1.4 billion (£1.2 billion), up 155% from mid-2023.

Design and scope changes

The cost increases are primarily due to significant design and scope changes, including maximum covering of the ring road and additional ‘liveability’ improvements. ‘These made the project more expensive, but the benefits to the surrounding area also increased with each intervention,’ says Lantis chief executive officer Luc Hellemans. ‘The Oosterweel project has long since ceased to be a mobility project, it is a welfare project for Flanders.’

Completion dates have also been pushed back by two years, with section 3A now due for completion in 2032 and section 3B scheduled for 2034.

One of the reasons for the delay is the discovery per- and polyfluoroalkyl substances (PFAS) contamination, which has required additional site surveys and studies as well as installation of water treatment plants. Both Lantis and its NEC contractors say they are doing their utmost with the ECC programmes to keep the timing as tight as possible.

Collaboration between contractors

In August 2024, section 3A contractor Rinkoniên Oosterweelknoop started installing 3.2 km of diaphragm walls as a permanent cofferdam for building the below-ground sections of the interchange. The 140,000 m³ of concrete needed for the walls is initially being supplied by section 3B contractor Roco from its concrete plant at Straatsburg dock.

Amanda Meeder, coordinator of the project’s NEC4 ECC Knowledge Centre, says, ‘This is one of many collaborations between the NEC contractors. Collaboration has been further improved by around 650 employees of Lantis, the NEC contractors and technical installations contractors Ocotech moving to a new central campus in October 2024. This is now the beating heart of the Oosterweel right-bank project’.

Meeder says the project teams are becoming familiar with putting NEC processes into practice. ‘By November 2024, nearly 1000 early warnings had been notified, with 69% from the contractors and 31% from the project managers. About 250 compensation events had been accepted and implemented, 58% of which were due to scope changes.’

However, she says there is still a learning curve with NEC. ‘Many project team members have previously only worked on traditional contracts, with a classic division of roles and responsibilities. Typical questions to the NEC4 ECC Knowledge Centre include when to notify an early warning, how early warnings relate to compensation events, when a problem is a defect, and how this relates to the contractor’s quality management in the scope.’

Major construction works in 2025

Going forward, section 3B contractor Roco will start top-down construction in early 2025 of the first five canal tunnel sections, between Samga and Straatsburg docks. A steel-sheet-piled cofferdam was begun in May 2024 and this started being pumped out in December 2024.

In 2025 the contractor will also start demolishing the Merksem viaduct section of the ring road. It will then be rebuilt and mostly covered in a new cutting while traffic runs on a temporary elevated bypass alongside. Work started on the temporary bypass in early 2024, with the northbound section due to be commissioned in 2025 and the southbound section in 2026.