Tone Bridge Tangier Way Taunton

Tied-arch design

Achieving shallow construction depth was a key driver. By placing a slender steel girder each side of the carriageway supported by feature arches overhead, the engineers were able to minimise the depth of the crossbeams, and use elegant tapering cantilevers to support the footways on each side. This also kept the deck edges very thin in line with the desired objective.

The arch has an open skeletal structure with solid chords separated by triangular crossframes. In order to achieve the desired lightness, delicacy and transparency, the engineers used a clever device with twin plates in the crossframes to create vierendeel action to restrain the arch chords and enable their diameter to be minimised. This also enabled the stainless steel hangers to fit neatly within the openings and form a fan-shaped array in elevation.¹

“We are very pleased that the whole operation went so smoothly this morning.” said Morrison Construction site manager Bob Stevens. “The fact that it took just an hour to perform such a complex manoeuvre is testament to the six months of careful planning by Galliford Try, Somerset County Council and Mabey Bridge Fabrication. It really is wonderful to see the new River Tone bridge in place, and to have been involved in leaving a lasting legacy to the improvement of transport in Taunton.” Consultant Flint & Neill designed the bridge, and the highway design was carried out by Atkins.

opened by Transport Minister Norman Baker, September 27th 2011

The Taunton Third Way bridge, with its distinctive bowstring arches, won best Civil Engineering Project (costing up to £3 million).

The principal contractor was Galliford Try, the designers were Flint & Neil, and Moxon Architects.

The bridge spans 36 metres over the River Tone in the centre of Taunton, designed for road traffic, pedestrians and cyclists. The entire 220 tonne structure was assembled alongside the river and lifted into place in a single operation by one of Europe’s largest cranes. (1)

Tone Bridge spans 36m and carries Tangier Way over the River Tone in the centre of Taunton. It forms part of the Taunton Third Way road scheme which was built by Somerset County Council to relieve traffic from the town centre and provide access for the regeneration of the Tangier area. Principal contractor Galliford Try was on site between 2010 and 2011. Civil engineer Flint & Neill with Moxon Architects won the competition to design Tone Bridge. It is a steel tied arch with a steel orthotropic deck (ie steel plates stiffened by
other transverse and longitudinal steel plates and trusses) and stainless steel hangers. The bridge was fabricated off site by Mabey Bridge Ltd and assembled on the adjacent riverbank. The total weight of the superstructure is 247 tonnes and it was lifted in one piece by a 600 tonne crawler crane onto reinforced concrete abutments in an operation lasting less than one hour.

Tone Bridge was the centrepiece of the official opening of Taunton Third Way by Transport Minister Norman Baker MP on 27th September 2011. It won the 2012 British Construction
Industry Award for civil engineering projects with a value up to £3,000,000. The judges commented that: “This was a great example of how architects and engineers can work together to design an elegant solution while addressing the buildability and construction issues”. (2)

2. https://www.ice.org.uk/ICEDevelopmentWebPortal/media/Documents/Disciplines%20and%20Resources/Information%20Sheets/Final-Bridges-along-the-River-Tone.pdf