AWARD: Copr Bay Bridge, Swansea

A landmark gold-painted steel pedestrian and cycle bridge reconnects Swansea city centre with its renowned coastline and beaches.

FACT FILE
Architect: ACME
Structural engineer: Ney & Partners
Steelwork contractor: S H Structures Ltd
Client: City & County of Swansea

Forming an integral part of Swansea’s large-scale urban regeneration, Copr Bay phase one has reactivated a previously underutilised plot of land by delivering a state-of-the-art, 3,500 capacity arena, comprising a live performance area and conference centre, as well as new public realm including the city’s first new coastal park since Victorian times, high-quality, new social housing and retail space for local businesses.

Creating a highly visual statement and connecting this development to the city centre by spanning Oystermouth Road’s six lanes of traffic, a gold-painted steel pedestrian and cycle bridge has been installed.

The completed Copr Bay Bridge is said to provide a new gateway for Swansea and is a celebration of the city’s past, present and future.

Designed by a local artist Marc Rees and architectural practice ACME, the 49m-long single span bridge is an eye-catching structure that 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, each dispersed across the panels, create a visually interesting pattern.

The perforations are abstracted and exploded silhouettes of swans, inspired by the emblematic Swansea bird. The bridge colour and lighting are designed to move in synchronisation with the illuminating facade of the arena, to create a Copr Bay district that pulsates with life at day and at night.

In acknowledgment of Copr Bay’s history as the centre of coal and copper production, the bridge is said to have the colour of freshly smelted copper.

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.

“The choice of steelwork was 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.”

Fabricated, supplied and installed by S H Structures, on behalf of the main contractor, the 140t bridge was delivered to site in sections, consisting of four deck pieces, six roof sections and 11 side panels.

The roof sections measured 10.5m × 4.1m × 600mm and the side panels were 2.8m × 6.9m × 15mm.

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

“As the deck is only 15mm-thick and needed to be split longitudinal for transportation, the open end was extremely lively, both when being transported and during lifting,” says S H Structures Project Manager Will Sharples.

“We had to come up with a bespoke transport lifting beam that strengthened the deck and allowed a multiple eight-point pick up procedure.”

Once onsite, the bridge deck was assembled on temporary works positioned in an area 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.

After the bridge structure was in its final position, the steel deck had an anti-slip resin and aggregate finish applied.

Mr 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. The council’s transformation of the city is creating a modern, vibrant city and opportunities for residents, artists and businesses, both those who call Swansea their home and those who should.”

In summary, the judges say the innovative stressed skin design and the quality of the manufacturing have resulted in an exemplary project.