The design is inspired by the pastoral and historic context to create a landmark ‘millennium’ bridge at the frontier between Celtic and Roman Britain.
Hadrian’s bridge is conceived as a meandering elevated walk and cycle ride through ‘flexible’ geodesic structure. The bridge structure is threaded through the existing bankside woodland, minimising impact to the woodland and flood plain and their habitats. The sinuous form of the bridge alludes to the geological shifting path of the river beneath and in contrast with the linear form and alignment of Hadrian’s fortified wall. The new crossing offers a scenic journey through woodland canopy across the River Eden.
Hadrian’s Bridge is formed of two lengths which pass at the midpoint of the river crossing. This transition point, symbolic of the historic frontier, is a viewing/ resting point and potential location for an interpretation area. This area is articulated externally by overlapping metal plates attached to the structure (evocative of Roman Legion armour) with display information etched onto the inside of the panels. The rest point is strategically located to optimise the delightful river views north towards Scotland and south towards the site of Hadrian’s Wall Bridge crossing.
The bridge meanders through the woodland canopy and minimises impact to the bankside landscape and habitat. The bridge span is reduced by a central column which articulates the transitional mid point. To optimise the relationship between the 3.5metre width and achieving a structurally efficient depth the elliptical bridge section is tilted, which lends further to the dynamic sculptural quality to the bridge. The bridge falls gently at a gradient of 1:20 to permit convenient access for disabled users and obtain the necessary height above the highest flood level.
The construction of the geodesic structure is conceived as a simple ‘kit of parts’ to maximise economies of duplication and prefabrication. The structure is ‘systematised’ around cast ductile iron pinwheel flange nodes. The nodes are interconnected by four ‘struts’ to form the continuous geodesic structure. The struts are of either laminated timber (European red cedar) or alternatively steel hollow sections. The nodes provide the fixing locations for the external stainless-steel cladding, the timber decking and balustrade/ handrail. The structure is prefabricated to achieve quality and economy and then transported to site and erected in sections. Timber deck boarding provides a natural durable surface and will give a ‘rumble strip’ effect to reduce potential speed of cyclists. A service void beneath the timber deck enables uninterrupted routing for services. The balustrades contain the lighting for the bridge and are completed with ‘chainmail’ mesh to discourage climbing.
The new Hadrian’s Bridge forms a pastoral, poetic and dramatic new crossing for pedestrians and cyclists to link the neighbourhoods to the north and south of the River Eden and establish a new interpretative route linking with the New Millennium Gallery and Carlisle city centre.
