HS2 engineers have finally slid the tallest bridge on the scheme into position above Birmingham’s Cross City railway line after overcoming major welding challenges that delayed the operation by almost a year.
The 4,200-tonne Curzon 2 structure was moved 180 metres in a complex three-stage launch and is now locked onto permanent piers, creating a new 40m-high landmark on the approach to Curzon Street Station.
The successful launch marks a major milestone on the Birmingham section of the railway and removes one of the most technically demanding structures on the route.
Portuguese engineering and metal construction specialist Martifer manufactured the structural steelwork for the 150m-long Warren truss bridge. Individual steel sections weighing up to 85 tonnes were fabricated at the firm’s facilities in Portugal before being shipped to the UK for assembly by the Balfour Beatty VINCI joint venture.
The launch had originally been expected last year but was pushed back as the project team grappled with complex welding requirements and an industry-wide shortage of skilled welders needed to complete the giant truss.
A workforce of 250 engineers, welders and apprentices spent three years constructing the superstructure on a tightly constrained site between the River Rea and the operational railway.
Curzon 2 during extensive welding task
The bridge’s distinctive 24m-high weathering steel truss is made up of 670 individual steel sections welded together to create the striking triangular structure.
At its highest point, the structure rises more than 40m above ground level – roughly the height of a 10-storey building – making it the tallest bridge on the HS2 route.
Onder Akin, senior project manager for Balfour Beatty VINCI, said: “This has been an incredible challenge and I’m extremely proud of the team who worked around the clock, in all weather conditions, to complete this magnificent structure.”
The launch operation was completed in three stages. The bridge was first pushed 50m towards the railway boundary during overnight possessions. A further 93m move carried the structure across the Cross City line during a planned closure between Birmingham New Street and Lichfield Trent Valley. The final 37m push secured the bridge onto its permanent bearings.
The 4,200-tonne structure was pulled into position using a strand-jacking system comprising two cables beneath the bridge to drive it forward and a third cable acting as a brake to control the movement.
The bridge forms part of the Curzon approaches, a network of five viaducts carrying HS2 trains on the final mile into Birmingham’s city-centre terminus.
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