RDG Engineering were approached by The Eden Project to provide a temporary pedestrian bridge to cross a 60m valley between the east and west banks of the site. A classic 2 pinned arch, with a suspended footpath for the public, was designed to be sympathetic with the surroundings. Robust aluminium modular components were used, to ensure the geometry of the arch was capable of transferring the imposed loads to the abutment supports at each end.
The original bridge wasn’t designed to support a canopy; the client request came 12 months after the commissioning of the bridge due to a spell of particularly bad weather. The bridge structure and foundations couldn’t easily be strengthened, so an independent canopy structure was devised. The stability of the central section of the canopy could not be maintained under wind loading without some form of lateral restraint. The solution was to install dash-pot dampeners along the central span of the bridge to allow a degree of lateral movement, improving the aerodynamic characteristics of the canopy.
In keeping with the environmental priorities of The Eden Project, a mixture of recycled materials were used. Folded metal decking overlain with aluminium deck plate was used for the anti-slip wearing surface, cast in situ reinforced concrete was used for the bridge abutment foundations, hollow steel sections were used for the canopy main stay structures and canopy damper arms, extruded aluminium profile was used for the canopy cladding support and the canopy cladding was manufactured using translucent, UV stable, self-cleaning plastic sheeting.
Originally the bridge was to remain in place for 5 years however this was later extended to 8.