e-mosty 4 2016 Arch Bridges | Page 64

SUMMARY 1. Introduction An 89m, twin network arch bridge was designed to span the River Irwell in the North of England. The bridge will carry a twin, bidirectional track arrangement as part of the Ordsall Chord intervention. A number of requirements and constraints were imposed, which posed challenges to both the design and construction teams. Effective use of BIM technologies and processes and the adoption of a collaborative approach by all parties involved, including the early appointment of the Steelwork Fabricator were catalysts to the successful completion of the design phase of the structure. The merits of the wider team collaboration can also be seen during the construction phase. The River Irwell Bridge forms part of the Ordsall Chord, which is a new elevated railway viaduct currently under construction in the heart of Manchester in the North West of England. The Chord itself is part of the wider Northern Hub and Electrification Programme, which will improve the capacity of the Railway network and contribute significantly to the economic prosperity of the region. A visualisation of the Ordsall Chord is shown in Fig. 1. This is the first network arch railway bridge in the United Kingdom. It is also believed that the arrangement of asymmetric arches, open section longitudinal ties and type of loading constitute a world's first variation of a network arch bridge. The structure is currently under construction and due for completion in 2017. The viaduct is approximately 300m long and connects two existing masonry arch viaducts, namely the Castlefield and Middlewood viaducts. It crosses a site with significant historic value to both cities of Manchester and Salford, which used to be the epicentre of the development of railways in the UK. Specifically, the Viaduct crosses Water Street, Stephenson's Viaduct, which is a Grade II listed Heritage structure, the River Irwell and Trinity Way, which is part of the Manchester and Salford Inner Relief Road. The River Irwell Bridge is a steel network twin arch, which is the first of this kind of bridge in the UK, spanning 89m across the River Irwell. Fig. 1: Visualisation of the Ordsall Chord 4/2016