Balfour Beatty Mott MacDonald
Mabey Bridge Ltd
Interserve Construction Ltd
The structure is a steel hybrid box girder/half- through trough. This efficient structural form gives both excellent torsional rigidity and allows the bridge to have a low overall structural depth.
The structure tapers over its length, with greatest depth at mid-span and minimal depth at each end. This form provides the structural depth where it is needed the most in the simply supported span.
Visually, the gently curved, sculpted exterior form is deliberately understated with a simple uncluttered exterior. Internal steel stiffeners define a series of gradually morphing skeletal ‘ribs’. These regularly spaced ‘ribs’, required to stiffen the cross section, constantly change shape as one travels across the bridge.
The main bridge was installed within an 8- hour night-time closure, with ramps and stairs being erected on subsequent nights to minimise disruption to the travelling public.
Long approach ramps required complicated curved and twisted box spine beams leading to the main span. The elegant main span is formed of a cleverly shaped box section with upstand edge beams and neatly detailed post and mesh safety barriers providing a visually shallow profile.
The bridge provides a much needed safe pedestrian and cycle link across the busy A27 road.