26 March 2011

Taunton's Third Way bridge installed

A new road bridge has been lifted into place in Taunton, Somerset. It spans 36m across the River Tone, and is part of a scheme to relieve town centre congestion. I believe the bridge cost about £1.5m, although a number of seemingly unrelated figures are reported online.

The designers of this attractive little bridge are Flint and Neill with Moxon Architects. The most obvious feature is the pair of trussed arches, a little reminiscent of Flint's masts for the Lockmeadow Footbridge.

Each arch is triangular in cross-section, with four ribs braced apart by Vierendeel-style frames. There are two circular ribs at the upper corners of the triangle, and two rectangular ribs close together at the lower corner. The form provides stiffness and stability against buckling in both lateral and vertical directions. The bridge deck crossbeams are suspended from hangers which are perpendicular to the arch.

I'm not entirely convinced by the various sections used for the arch members, they seem a little ungainly. I wonder whether all-circular members would have looked better.

The bridge was erected in a single 218t piece by a 600t capacity strut crane. The main contractor is Galliford Try, with Mabey Bridge the fabricator.

Judging from the various images on the Moxon website, the highway bridge is to be complemented by a set of nearby footbridges, part of a separate regeneration scheme, which include a spine beam deck and another arch structure, both pictured below.

Taunton will very quickly become home to a fine set of contemporary structures.

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