HS2: M6 Viaduct Launch: Rail Innovations & High-Speed Rail Trends

HS2 Makes Significant Progress with M6 South Viaduct Launch

A major milestone in the HS2 project has been reached with the successful launch of the first section of the M6 South viaduct’s ‘East Deck’ over the motorway this past weekend. This complex engineering feat involved sliding the 119-meter-long deck section over a slip road adjacent to the M6, minimizing disruption to motorists. This critical infrastructure project will carry high-speed trains, ultimately easing pressure on the existing rail network and improving passenger and freight services. The ‘East Deck’ will carry two tracks towards London, while the adjacent ‘West Deck,’ scheduled for completion next year, will carry trains heading towards Birmingham and the north. This article will explore the innovative construction methods and the collaborative efforts behind this significant advancement in railway infrastructure.

Innovative Construction Techniques to Minimize Disruption

The HS2 project team, led by main works contractor BBV (Balfour Beatty VINCI), and supported by specialist steelwork company Victor Buyck Steel Construction (VBSC), employed a strategic approach to minimize disruption to road users. The viaduct deck was assembled offline, adjacent to the motorway, and then slid across in stages over three separate weekends. This method allowed for incremental increases in the deck’s weight, starting at 1,300 tonnes and reaching 3,290 tonnes for the final slide, which will extend the deck over the main M6 carriageway and subsequently the M6-M42 link roads. This innovative “launching” method, with the deck units pre-cast on top of the steel structure, greatly reduced the number of motorway closures required. National Highways Regional Director for the Midlands, Victoria Lazenby, highlighted the organization’s appreciation for the innovation, stating that the project team’s efforts have helped reduce the impact on road users.

Engineering Precision: The Launch Process

The intricate launch of the viaduct relied on a sophisticated system of strand jacks, which moved the section at an average speed of twelve meters per hour. These powerful winches, using non-stick pads—similar to the material found on household frying pans—minimized friction during the slide. A 36-meter-long temporary launch nose was installed at the front of the structure to guide the viaduct and lessen the weight of the cantilevered section. The structure is now in its temporary position, with the next section of the viaduct scheduled to be assembled. The structure’s temporary stability is provided by equipment located on the piers and abutments. Russell Luckhurst, Balfour Beatty VINCI’s engineer leading the delivery of the works, emphasized the significance of this achievement and highlighted the focus on the upcoming phases of the project, including two further launches later this year.

Material Selection and Structural Design

Each viaduct span is constructed from a hollow double-box structure made of weathering steel. This specific steel type features a natural protective layer of oxidization, resulting in a distinct “rusty” appearance, which eliminates the need for regular repainting and, in turn, minimizes maintenance requirements. The viaducts are supported by four pairs of concrete piers, with the tallest pier reaching a height of 9.9 meters. A 4.5-meter-high parapet will be installed on the side facing Chelmsley Wood, designed to reduce noise and disturbance for local residents from passing trains. The structural design was a collaborative effort by Balfour Beatty VINCI’s Design Joint Venture, which includes Mott MacDonald and SYSTRA.

Collaboration and Stakeholder Engagement

The success of this project hinges on strong collaboration between multiple stakeholders. HS2 Ltd’s Senior Project Manager, Liam Kenney, acknowledged the hard work of the team and the early opening of the road to traffic, which was achieved eleven hours ahead of schedule. BBV worked closely with National Highways and other key local stakeholders, including the NEC and Birmingham Airport, to ensure smooth operations. Tom Dutton, Senior Design Co-ordinator for the Mott MacDonald SYSTRA DJV, highlighted the team’s collective effort and the collaborative spirit in overcoming the complex challenges of the temporary works, the fabrication of the steel diaphragm, and the launching of the viaduct decks over the M6 motorway itself.

Conclusion

The successful launch of the first section of the M6 South viaduct signifies a major leap forward for the HS2 project, showcasing innovative construction techniques and collaborative efforts to minimize disruption. This milestone reflects a commitment to efficient project management and the adoption of cutting-edge engineering solutions. The multi-stage approach of sliding the viaduct deck, combined with the use of weathering steel and optimized structural design, not only reduces the impact on road users but also contributes to long-term sustainability. The project’s success will set a precedent for future infrastructure projects and demonstrates how the rail industry can efficiently integrate innovation into existing infrastructure. With further launches planned, the completion of the M6 South viaduct will significantly improve rail connectivity and capacity, supporting future growth and the modernization of the UK’s railway network.