Detailed designs for a new twin viaduct to carry HS2 services into Curzon Street station through central Birmingham have been revealed, and will today go before the city council’s planning committee.

Consent is already in place for the viaduct via the HS2 Act, but HS2 Ltd is seeking approval from the planning committee for the details. The application only relates to the railway decks and associated piers, as the works underneath have been consented through the Curzon Street application. Plans for proposed landscaping will be submitted at a later date.

The structure, being created by BBV (Balfour Beatty Vinci JV), will comprise two consecutive viaducts extending from Curzon Street station to the existing Cross City line.

The first viaduct, known as the Curzon No. 3 viaduct, leaves the back of Curzon Street station in four separate decks. They then come together around the point of crossing the Digbeth Branch Canal to form the second viaduct, known as the Lawley Middleway viaduct.

The four-pronged Curzon No. 3 viaduct will measure approximately 300m in length and the superstructure will be constructed as a concrete deck that would be cast in situ.

The Lawley Middleway viaduct will measure approximately 213m in length. This element of the structure would be constructed with a steel deck.

A further viaduct, known as Curzon No. 2 viaduct, will then continue from the end of the Lawley Middleway viaduct, but it will be consented in a future planning application.

At the intersection with the canal, the superstructure has been designed to include coffers which both seek to minimise the amount of concrete needed in the structure and provide visual interest when viewed from below.

The two viaducts will be supported by 35 reinforced concrete piers. In addition to these, four bespoke tripod piers are proposed for the section of the viaduct that crosses the Digbeth Branch Canal. These tripod piers would be made of weathered steel as an ode to the historic canalside cranes.

Either side of the railway, deck parapets are proposed. Above the section of the deck that over sails the Digbeth Branch Canal the bottom third of the parapet includes a pattern which references motifs found in the ironwork of historic bridges in Birmingham.

Cross section showing weathering steel tripod piers and historic bridge motif

Where the proposed deck is split into four sections, a lighter parapet is proposed on the inside edge of each section of the deck. These parapets would be made with a combination of precast concrete and steel. This approach has been adopted to seek to increase the natural light under the deck.

The application states that there is an ambition to maximise the opportunities to create usable and flexible public space under the viaduct.

The viaduct will run in close proximity to many heritage assets. It will run parallel to, and briefly above, the Grade II listed 1838 railway viaduct that stretches over the Digbeth Branch Canal and reaches Curzon Street station. The station itself is Grade I listed and the historic part of the Lawley Street railway viaduct is also nearby. Historic England reports that it is satisfied that its concerns have been addressed in the new plans.

The previously discovered train maintenance roundhouse – the oldest in the world – is also beneath the viaduct, but has been re-covered until completion of the works.

The planning officer has recommended to approve the plans.

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Tagged with: Birmingham Curzon Street Curzon Street Station hs2

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