Structural engineer Flint & Neill and Moxon Architects design an original and contemporary bridge
This is a good example of design excellence, achieved at a very economic price. The bridge carries a highway, cycleways and footpaths over the River Tone near Taunton town centre. The tied-arch design is characterised by a delicacy and lightness achieved mainly through the clever use of a skeletal steel lattice for the arch and very slender deck edge treatment.
The client specifically stated a strong desire for high quality. The brief called for an original and contemporary design, and a sense of lightness particularly in the parapets and edge details, avoiding details such as standard vehicle barriers along the bridge edges. This struck a chord with the designers, Ian Firth of Flint & Neill and Ben Addy of Moxon Architects, who wished to use a light and delicate pedestrian parapet to maximise slenderness and enhance enjoyment of views from the bridge deck.
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.
Special timber benches on both sides enable pedestrians to pause and enjoy the river environment, physically and safely separated from the roadway behind.