Multi-Stage Deck Launch Underway for HS2 Viaduct

Construction of the twin viaducts that will carry HS2 trains over the M6 near Birmingham Airport has progressed with the completion of the first section of the East Deck. Measuring 119 meters, this segment is part of the 320-meter-long M6 South viaduct. To minimize disruption, both viaducts are being assembled adjacent to the motorway and will be slid into position over several weekends. The first slide is scheduled for June 7–8, with two additional weekend closures planned to complete the crossing over the motorway and M6-M42 Link Road.

Incremental Launch and Engineering Approach

The launch process is being conducted in multiple stages. Each section of the deck is added behind the previous and pushed forward using strand jacks, which operate at a speed of six to eight meters per hour. The sliding occurs over low-friction pads to control movement. The deck is being pushed on a slight incline, with a height differential of 4.2 meters between the starting and ending points. This will gradually increase the load from 1,300 tonnes to approximately 3,000 tonnes as construction progresses.

Design and Future Works

The viaducts are formed using a double-box hollow section composed of weathering steel, which develops a protective oxidized surface to minimize future maintenance. Each structure will be supported by four pairs of reinforced concrete piers, the tallest standing at 9.9 meters. A 4.5-meter parapet will be installed along the edge facing Chelmsley Wood for noise mitigation. The second viaduct, known as the West Deck, is scheduled for assembly and launch in 2026 using the same method and will require four slides to complete the crossing.