Project Ordsall Chord Location Manchester, UK Client Network Rail Expertise Lead designer including civils and Major bridge design in JV with Aecom chord 2018 More than £1bn will be spent on railway Royal Academy improvements between 2014 and 2022 in of Engineering the North of England. One of these ‘Great Major project award North Rail Projects’ is the Ordsall Chord. 2 I Mott MacDonald I Ordsall Chord Ordsall Chord I Mott MacDonald I 3 Connecting communities and supporting growth The Ordsall Chord links up three Manchester city centre stations for the first time, reducing congestion and allowing hundreds more trains to run each day. It is only a 300m stretch of new track, but the Ordsall Chord in Greater Manchester is a piece of engineering that will boost the local and regional economy with knock-on effects felt across a much wider area. The viaduct carrying the track connects existing lines through Manchester’s Victoria, Oxford Road and Piccadilly stations. Accommodating it involved realigning existing track, widening viaducts and laying new track, building new bridges, removing redundant “There is virtually The UK’s first network arch bridge height difference between the 2.5m tall rib section structures and restoring heritage features. All civil The River Irwell crossing is the first network arch and 2.8m tall Trinity Way bridge girder. Brian engineering works were designed by the Aecom Mott no element of bridge in the UK. The structure consists of a tied continues: “The most critical design cases arise MacDonald joint-venture. New public spaces have also repeatability across arch with a network of hangers. This arrangement during construction, when the lattice is incomplete, been created to allow the area’s rich industrial history creates an incredibly robust and efficient structure or if the hangers are accidently damaged or need to be fully appreciated. the different parts – essential for supporting heavy railway loads. replacing. Since the network arch is asymmetric, of this project... a very large number of critical scenarios can The Ordsall Chord connects to the existing Chat “A network arch uses a lattice of hangers to provide develop, which had to be assessed individually.” Moss viaduct to the north and Castlefield viaduct the network arch significantly greater stiffness and robustness than a to the south; both had to be widened. The Chord is totally unique.” conventional bowstring arch bridge, restraining in-plane Building the Ordsall Chord was extremely complex, itself is made up of three components: the River buckling of the arch ribs more efficiently,” explains adds Mike Pedley, senior construction manager Irwell crossing, a concertinaing architectural feature Mike Pedley Aecom-Mott MacDonald JV engineering manager Brian with contractor Skanska-Bam Nuttall JV. “There Senior construction manager known as the ‘cascades’, and the Trinity Way bridge. Skanska-Bam Nuttall JV Duguid. The structural form also makes a significantly was virtually no element of repeatability across The River Irwell crossing is a network arch bridge shallower arch rise achievable, which is in keeping the different parts of the project. Twenty-five with weathering steel arch ribs, while the Trinity Way with the scheme’s original architectural concept. precast concrete arches were built on the project bridge is a 100m long composite steel deck with to support the expanded viaducts. Each one is weathering steel girders. The cascades, also made from Spanning 89m across the river, the arch is made different and the network arch is totally unique. weathering steel, connect these two structures. The up of two ribs that incline inwards 6° to the vertical. Managing that variety was inevitably challenging.” surface of these key members develops a protective The bridge’s composite steel and concrete deck is patina of rust over time, giving the Ordsall Chord suspended via two networks of steel hangers. In The team received the prestigious 2018 Royal its distinctive reddish-brown colour and outlines its elevation, the ribs taper so that their cross-sectional Academy of Engineering major project award in fluid curved shape prominently on the landscape. height decreases from 2.5m to 0.7m along their recognition of the collaboration and engineering length. The cascades accommodate the 300mm skill needed to deliver this project. 4 I Mott MacDonald I Ordsall Chord Ordsall Chord I Mott MacDonald I 5 The Ordsall Chord Creating the three-in-one Ordsall Chord viaduct required many other The River Irwell crossing Construction site changes to be made in the area This network arch bridge, with inclined and The network arch bridge (minus tapering ribs, has a network of hangers hangers) was first erected on to support its deck. It is an extremely Museum of temporary platforms in this location stiff structure with a shallow profile. (See Science and before being lifted into position River Irwell Victoria N detail of network arch cross-section) Industry (MSI) SALFORD The cascades A 16m long curving beam MANCHESTER with profiled web stiffeners Piccadilly continue the ‘crease’ Ordsall Chord line of the River Irwell crossing’s arch ribs Weathering steel Deansgate Oxford Road 1km River Irwell 3 Castlefield viaduct 1 Built in 1845 and widened 2 as part of current works Middlewood viaduct Built in 1845 and widened as part of current works New public space Stephenson’s bridge Named after engineer George Stephenson’s 1830 railway which was carried Trinity Way bridge N by this bridge, this Grade Web stiffeners applied to 1 listed masonry structure the 2.8m tall girders of this is now part of MSI and has composite steel bridge are been repaired and restored profiled to continue the as part of current works ‘crease’ line of the River Irwell crossing’s arch ribs ‘Ghost’ pier A 19th century steel girder bridge was demolished, leaving just one pier. Its removal allowed essential repairs to Stephenson’s bridge to take place, and opened up views onto the structure Network arch K-bracing cross-section Provides restraint to arch ribs in plan Tapering arch rib Hexagonal cross- 6° sectional shape exhibiting a ‘crease’ River Irwell footbridge line on elevation Replaces original Prince’s bridge Varies with a 50m long steel structure (14.3m which was designed in 3D and max) delivered as a digital file • The Ordsall Chord will improve rail capacity and Pair of hangers connectivity across Manchester 85, 90 or 100mm • Some 3.2km of track have been altered and 350m diameter solid steel bars of viaduct widened to connect three city centre stations • The project includes restoration and repair of heritage Tie beam structures and creation of new public spaces 15.0m overall 6 I Mott MacDonald I Ordsall Chord Ordsall Chord I Mott MacDonald I 7 Super model River Irwell footbridge was designed in 3D Legacy and vision Ordsall Chord’s Network Rail and its producing a digital 3D model remained under “On the Ordsall Chord, using only a 3D model to contractors came together model of the footbridge the ownership of the JV the fabricator acted as an deliver the structure. This success owes as part of an alliance, over the River Irwell with and gave Severfield an intelligent CAD resource, saved greatly on drawing a great deal to forming a single team that no need for additional intimate understanding of applying expertise in 3D production time and total shared the project’s risks, 2D drawings. design development so modelling, minimising the design cost. the client and rewards and resources. that steelwork detailing need for later rework. It project team’s Key roles were filled Building information developed from the start. reduced both the design “Everything built on this by ‘best-for-project’ modelling The model was also programme and the footbridge including the collaborative personnel, regardless of The Ordsall Chord was used to co-ordinate time taken to prepare nuts, bolts, stiffeners and approach to their employer. Design delivered to BIM Level 2, reinforcement design for fabrication.” The BIM welding, was modelled,” team members took which demands a high and detailing. model included all major explains Brian. procurement on technical approval level of inter-disciplinary structures as well as and project roles for Network co-ordination. Design “The model and drawings foundations and existing “Two-dimensional Rail. Staff from steel and construction data were approved by all underground services. steelwork drawings were delivery. fabricator Severfield were was passed on digitally parties, but were ‘owned’ completely unnecessary embedded in the design to the client for future by the engineer, who River Irwell footbridge because the designer, team, for example, to help asset management. The certified the design,” – 3D design fabricator and future prepare the BIM model 3D model of the network says Brian Duguid. Pedestrian access over asset owner could and steelwork drawings. arch bridge was produced “This is different from the river is via a new 50m interrogate the model. Early co-ordination BIM allowed all aspects of the A willingness to operate by Severfield’s modellers, the traditional process, long steel footbridge. The We worked very hard to structure to be scrutinised in a different way led who were co-located in where engineers usually team decided not to make that possible.” directly to major design the offices of the Aecom- prepare their own generate conventional innovations, such as Mott MacDonald JV. The model and drawings. 2D steelwork drawings, 8 I Mott MacDonald I Ordsall Chord Ordsall Chord I Mott MacDonald I 9 Network Rail project director Mike Heywood believes that the Ordsall Chord brings together three important features: respect for the area’s heritage, a key piece of rail infrastructure and the prospect of regeneration. “With many of the people working on the project being local to Manchester, the team had a strong connection with the project and its aims.