Part of the Curzon Street Station Approach area, Curzon Viaduct No. 3 and Lawley Middleway Viaduct are just part of four viaducts which will be connected between Duddeston Junction Viaduct and Curzon Street Station in central Birmingham.
The other viaducts include Curzon Street No. 1 Viaduct which is furthest from the station and Curzon Street No. 2 Viaduct which is still in the planning process.
Design refinements have led to a reduced construction programme using less concrete to build the viaducts providing positive benefits for both the environment and the local community.
The viaducts have seen a Design Joint Venture made up of Mott MacDonald, Systra and West Williamson & Partners architects who are all working for HS2’s civil contractor Balfour Beatty VINCI joint venture to design the impressive structures.
David Speight, Client Project Director at HS2 Ltd said: “We are very pleased that Birmingham City Council’s planning committee approved the plans for these viaducts. This decision represents a significant approval for HS2 in Birmingham city centre and means we are on track to bring high-speed rail to the West Midlands, increasing capacity and connectivity across the UK. In addition, our design refinements on the viaducts will bring a range of extra benefits, including reducing the construction time and materials, reducing the amount of carbon we need on the project.”
Nick Robertshaw, Project Manager from the Design Joint Venture Mott MacDonald and Systra said: “BBV and the DJV design team have brought their global expertise to tackle the significant engineering challenges involved in fulfilling HS2’s design vision for this iconic structure, which will provide a catalyst for social and economic development.
“This landmark milestone for the programme has only been made possible through the ‘one team approach’ facilitated by HS2 with Birmingham City Council, whose critical input and collaboration has enabled this achievement.”
Nick McGough, Director at Weston Williamson and Partners said: “The key design challenge of Curzon 3 was to address varied sites with differing technical requirements whilst providing both a level of consistency as well as ensuring the viaduct contributes positively to its surroundings. Toward the HS2 Curzon Street Station, the viaduct is over 60m wide and so the design maximises daylight under the structure through the introduction of light slots with a unique lightweight parapet design. Over the Digbeth Canal, the opportunity is taken to reference Birmingham’s canalside heritage whilst the large span required over Lawley Middleway is achieved through the use of heroic weathering steel girders which arch over the carriageway.
“This has only been possible through the close collaboration between architect, engineer, and construction team and Birmingham City Council’s support of the result is testament that this 21st Century structure will contribute positively to the local community and allow for unique spaces that will add to the life of the city.”
At almost 300 metres long, Curzon Viaduct No. 3 sees the height above ground and ground level differ as much as 5 to 6 metres. The amazing structure is 65 metres wide at its broadest point and is carried by 30 piers, with its approach to Curzon Street Station sees the deck widen from a single deck at the eastern end into four separate decks at the western end.
As the viaduct nears Curzon Street Station it widens into four separate decks in order to maximise daylight to the public space beneath. V shape piers have been designed to support the viaduct which also uses less space at ground level and also offers a side recess for possible future services to be visually integrated. As the viaduct separates into four decks, the V piers will also support the opportunity to develop a usable, flexible public space beneath.
The concrete V piers are substituted with four inverted steel piers as Curzon Street No. 3 Viaduct crosses the Digbeth Canal and is in reference to its heritage and the canal side cranes in Birmingham. The Digbeth Canal area will maintain its visually attractive area for the public with a mix of the contemporary HS2 infrastructure and the 19th-century canal.
During the development, the width of the viaduct has been cut down from 71 metres to 65 metres and the Curzon Street Pumping Station which was previously located south of the viaduct removed from the designs as water that gathers on the viaduct will be drained into either an attenuation pond which is an area of ground which stores excess water temporarily before releasing it in a controlled manner or an attenuation tank which would be located underground.