SSDA 2023: Copr Bay Bridge, Swansea

Designed by local artist Marc Rees and architectural practice ACME, the single span bridge is 12m wide x 7.5m high and has a structural skin of 15mm-thick steel plate. Featuring a distinctive gold paint finish, the side panel plates are perforated with numerous laser-profiled cut-outs and pressed into complex shapes.

The design is said to balance a contemporary aesthetic with references that celebrate the city’s heritage. The 2,756 laser-cut origami-inspired shapes, dispersed across the panels, create a visually interesting pattern. The perforations are abstracted and exploded silhouettes of swans, inspired by the emblematic Swansea bird.

Double-curved surface

The bridge structure offers a degree of protection from the elements. The steel has been rolled into a double-curved surface and butt-welded into a single tube. Openings have been cut into the sides where the structural stresses were lower, offering glimpses across the road, the arena and the new coastal park and to allow the bridge to glow at night from within.

ACME design director Friedrich Ludewig says: “The iconic arch stabilises the super-slender bridge deck and creates a new urban space floating over the road, enclosed by patterned steel offering glimpses across the road, the arena and the new coastal park.

“Steelwork was chosen primarily because of its structural properties and ability to span large distances. It gave the design flexibility to work with an interesting structural solution – essentially a deformed bow truss formed of plate steel – allowing the creation of the sculptural form, super-thin bridge deck and the opportunity to create a clear identity through the development of perforations in
the truss walls and application of a gold paint finish.”

The 140-tonne bridge was fabricated, supplied and installed by S H Structures on behalf of the main contractor. It was delivered to site in sections, consisting of four deck pieces, six roof sections and 11 side panels. The roof sections measured 10.5m x 4.1m x 600mm and the side panels were 2.8m x 6.9m x 15mm.

The largest steel elements to be transported to site – and also the heaviest – were the deck sections, measuring 24.5m x 6m x 2m and weighing 24.6 tonnes each.

‘Thrill of a lifetime’

Once on site, the bridge deck was assembled on temporary works adjacent to the bridge’s final location. The curved plates, which form the sides, arch and roof, were then welded into place, before the complete structure was given its final topcoat of gold paint.

The completed structure was then lifted onto self-propelled modular transporters (SPMTs) and manoeuvred onto its two concrete abutments during a Saturday night road closure.

Rees says: “It has been the thrill of a lifetime to be involved in such an iconic part of the regeneration of my hometown. Dylan Thomas infamously described Swansea as an ‘ugly, lovely town’ – whatever the merits of that when he said it, Swansea’s aspiration to change, grow and flourish is more than apparent now.”

In summary, the judges say the Copr Bay Bridge provides a dramatic new gateway to Swansea, with its striking form and colour acknowledging the bay’s history as a centre of coal and copper production.

Produced by BCSA and Steel for Life in association with Construction Management