Butterfly bridge sannam kalra

THE BUTTERFLY BRIDGEBEDFORD, UK

• The Butterfly Bridge. A footbridge over the section of the river, next to the Embankment, which is used for rowing.

• The bridge was opened by Big Ears in 1998 after an architectural competition and was notoriously expensive. • It was supposed to make a pontoon bridge used in the River Festival redundant and so pay for itself, but in fact

it is used as well as, rather than instead of, the temporary bride.

• The bridge, at 32m in span, has twin steel arches which are inclined like butterfly wings to produce a feeling of containment on the deck and, simultaneously, an openness to the sky.

• The deck extends onto the landscaped banks at each end to engage with the open space around the bridge and enable step-free access, with longitudinal deck lighting concealed at kicker level within the parapets.

Date Completed : 1997Architect: Chris Wilkinson Architects

Location : Bedford, UKEngineer: Jan Bobrowski and Partners

Client : Bedford Borough Council Contractor: Littlehampton Welding Ltd

Value : £375,000

The two inclined tubular steel arches form the primary structure from which the hardwood timber deck is suspended by means of a system of rod hangers connected to transverse steel bearers that are integral with the balusters supporting the handrails.

The two curved tubes support the suspended steel and timber deck with stainless steel cables. The contract included the concrete abutments which required accurate setting-out of fixing bolts, in particular those restraining the curved tubes.

In the context of the multiple factors informing the design, the result is functional on many levels. Its reason to be, a level and navigable crossing of the Great Ouse [in contrast to the steeply sloped existing suspension bridge], is a by-product of the more esoteric demands of the design problem. Structurally the composition is at the limits of its capability. Visually it is intentionally arresting and historically it is anchored to its site by reference to the existing. The design is a result of a collaborative application of art and engineering in contrast to Webster's engineering latterly perceived as art."