Footbridge at Princes Dock, Liverpool Centre for Architectural Research and Consultancy Unit
The primary bridge structure consists of a 'wishbone' that comprises a pair of canted wings of 406mm diameter x 16mm CHS tubes which rise in an arch and are welded together to form an overhead spine - a 406mm diameter x 32mm CHS tube.
It is supported by a series of nine hoops which run at 4m centres along the length of the bridge.
Although the structure is a consistent 2.55m wide at deck level, the hoops change in shape as they run from one side to the other.
At the city side, the first three hoops (see sections at E - E and D - D) are open at the top to support the wings.The next four hoops successively increase in height from 4.4m above the deck at section C - C to 5.1m at section B - B. The two final hoops rest on the ground and are 5.4m and 5.5m respectively above deck level.
Each hoop is T-shaped in section with a tapered web and a 160mm wide flange of 20mm thick plate.
The tops of the hoops are welded to a series of 710mm diameter steel rings - these are 50mm thick - which encircle the tubular wishbone members.
The deck is formed of 250mm wide extruded aluminium planks; these are perforated with small oval holes in order to allow glimpses of the water below.These planks are bolted at each side to a supporting steel angle welded to a 168.3mm diameter CHS.
The sides are trimmed with aluminium kick plates.
The cladding - perforated polyester powder-coated aluminium panels - and its carrier system are fastened to a series of vertical 100 x 100mm Tshaped sections which in turn are welded to horizontal 76mm diameter CHS supports.