To the north of the River Wensum in Norwich, land is under redevelopment to create 200 houses, 20,500 sq m of office space, an hotel, 1,500 sq m of retail space, restaurants and cafés. The masterplan includes a new pedestrian bridge providing direct access to the city centre from the Barrack Street site. Various constraints and statutory requirements necessitated extensive liaison with Norwich Council and the Broads Authority to deliver a satisfactory design.
Spanning a narrow 30m section of the Wensum, the deck needs to sit 2.9m above the water level to allow river traffic to pass unhindered. Long approach ramps are necessary to retain full accessibility for cycles and wheelchairs. To accommodate this, the bridge is 80m in length and curves to form a ‘J’ shape, aligning with the path along the southern bank. Minimising disruption to the river banks and traffic, the main deck is designed for fabrication offsite before being craned into position and connected to the back spans.
The structure is a double cantilever design. Its curvilinear form is supported on two slender columns located on the water’s edge. Resting on concrete pads with pile foundations, these pin-jointed columns support the steel beam, allowing for expansion. The angled form of the weathering steel box beam tapers at the top and spans around the inside curve of the J, forming the inner parapet. The deck cantilevers off the beam, constructed using a lattice of weathering steel cross beams, surfaced with timber in a pattern intended to naturally reduce the speed of cyclists. The outer parapet is lightweight stainless steel mesh.
Numerous constraints increased the original scope of the footbridge, the presence of which is integral to the success of the masterplan. Refinement of form and materials has produced an economical design using just three natural finish materials. Weathering steel, timber and stainless steel were selected for durability and low maintenance requirements — the bridge will remain the responsibility of the client.