HS2 Water Orton viaduct spans installed over existing railway

These spans are a relatively small, but critical, component of the Delta Junction – an expansive triangular intersection being built to the east of Birmingham for the new high-speed railway. 

The junction is formed of a complex series of interconnected viaducts, and other structures, taking the high-speed line over motorways, local roads, existing railways, rivers and floodplains, carrying HS2 services to and from Birmingham, as well as connecting to the mainline heading north and south. To maintain speeds of 360km/h on the mainline and around 200km/h on the approaches to Birmingham, the junction is spread out over a far larger area than a motorway junction – over 4km from south to north and over 2km from east to west. 

Designed by the Mott MacDonald SYSTRA Design Joint Venture, supported by WW+P Architects, the Water Orton viaducts will connect the mainline tracks at the north end of the junction to the spur leading to the new Birmingham Curzon Street Station, which also serves the HS2 rolling stock depot at Washwood Heath. Once complete, these two viaducts will stretch for around 1.4km each, crossing two railways, a river, local roads and the M42. 

The design of the viaducts was conditioned by contractor Balfour Beatty VINCI’s choice of construction method, which employs a mobile cable stay mast to temporarily support the partially completed span in a cantilever configuration (supported only at one end) until the installation of successive precast box girder segments reaches next pier. At this point the permanent post-tensioning cables are installed through the completed span allowing for the temporary cables stays to be moved forward to support the assembly of the next span. 

The Water Orton viaducts are not only an impressive feat of engineering but as elevated structures they also serve to maintain the continuity of the landscape.

Hani Benkhellat, Delta Junction Sublot Manager, SYSTRA Ltd

Balfour Beatty VINCI crews were able to safely complete the two parallel spans crossing above the existing railway line over the course of a six-day suspension of passenger and freight rail traffic, which had been meticulously planned years in advance and programmed to take place during the quieter Christmas period. Mott MacDonald SYSTRA Design Joint Venture’s deep implication in design and site support has been crucial in supporting the pace of construction activities, setting the contractor up for success in the completion of this strategic crossing within the allotted window. 

Hani Benkhellat, Delta Junction Sublot Manager at SYSTRA, said: “The installation of these spans is yet another crucial milestone on the project, which is taking form along the entire route. The Water Orton viaducts are not only an impressive feat of engineering but as elevated structures they also serve to maintain the continuity of the landscape. The construction of the viaducts is accompanied by related works to improve the landscape and community access through the creation of green spaces and a walking and cycling route. Flood management is also a crucial part of the design, along with the realignment of the River Cole, all supporting the projects’ sustainability mission.” 

Find out more about our work on HS2.