A31 Ringwood bridge replacement and road widening, UK

NEC contracts have been used successfully to upgrade a major trunk road in southern England. NEC Users’ Group platinum member National Highways engaged VolkerFitzpatrick through its NEC-based regional delivery partnership to undertake the £30 million A31 Ringwood bridge replacement and road widening scheme in March 2021.

Let under an NEC4 Engineering and Construction Contract (ECC) Option C (target contract with activity schedule), the work involved widening around 0.5 km of the existing westbound carriageway from two to three lanes between the Ringwood entry slip road and Verwood exit slip road. This included demolishing and replacing two 1930s life-expired bridge decks over the River Avon and Bickerley Millstream, with traffic running in contra-flow on the eastbound carriageway.

Due to significant environmental and ecological sensitivities, the works had to be carried out between April and November each year. A huge 750 t crane was therefore brought in to lift out the existing bridge decks in just a few large sections weighing up to 60 t, with pontoons installed on the waterways as part of the environmental mitigation measures. The demolition was carried out using rolling roadblocks to avoid the need for road closures and reduce the impact on road users.

The replacement bridge foundations were then installed using vibro piling to minimise disturbance to wildlife, after which new steel bridge beams up to 45 m in length were lifted into place. The decks were concreted in phases to allow for settlement, and the new carriageway was then surfaced and re-opened to traffic on budget and 12 days early in November 2022. Over 1600 trees and shrubs were also planted.

NEC project manager Mott Macdonald and NEC supervisor WSP were each engaged by National Highways under an NEC4 Professional Service Contract (PSC). The project was shortlisted for both the Transport Project of the Year and the Environmental Project of the Year in the 2023 British Construction Industry Awards. 

Well-understood contract

National Highways senior project manager Daniel Kittredge says NEC4 ECC Option C was the basis of its £8.7 billion 2019–2024 regional delivery partnership frameworks, for which VolkerFitzpatrick was one of two contractors appointed to the £350 million southeast and east lot. 

‘NEC has become a well-used and understood suite of contracts within the highway infrastructure business, and this commonality has improved the understanding of the contract within the project environment for both clients and contractors. This increased understanding has resulted in proficiency on both sides for delivering and managing schemes within the commercial environment.’

He says ECC Option C gave the project team the framework they needed to deliver the challenging scheme. ‘Nominated project managers on both sides had the delegated authority to agree how issues and conflicts could be solved at project level, which kept the scheme delivering at the pace required.’

Kittredge says the NEC requirement on the parties to act in a ‘spirit of mutual trust and co-operation’ allowed the collaborative nature of the integrated project team to develop, with an emphasis on transparency and honesty on both sides. 

‘Using the tools within the contract, such as early warning notices and compensation events, the NEC project manager and supervisor performed an invaluable service for the client project manager. They worked closely with the delivery partner to ensure all parties could manage scheme delivery within the agreed contractual parameters.’

He says the outcome is that the A31 at Ringwood was completed on budget and ahead of time. ‘The A31 is one of the region's most important roads, connecting Surrey, Hampshire and Dorset. The improved route will be more reliable, reducing journey times and providing capacity for future traffic growth.’

Benefits of using NEC

• NEC contract suite is well-used and understood by highway clients and contractors, resulting in proficiency on both sides for delivering and managing schemes.
• NEC requirement to act in a ‘spirit of mutual trust and co-operation’ allowed the collaborative nature of the integrated project team to develop, with an emphasis on transparency and honesty.
• NEC processes such as early warnings and compensation events together with NEC project manager and supervisor roles ensured successful scheme delivery.