Peace Bridge

Derry, United Kingdom

Year

2011

Duration

21 months

Cost

£14m

Location

United Kingdom

Project achievements

Connected communities

Helped to join previously divided communities. (modified)

Economy boosted

A million crossings in just over a year. Jobs created.

Used engineering skill

Challenging design for bridge engineers and construction.

Design a landmark structure to link historically divided communities

This new iconic cycle and foot bridge across the River Foyle is an innovative and complex structure. The project brief was to design a structure to link historically divided communities on the east and west banks, both physically and metaphorically.

It is designed as two identical halves, each suspended from a single, inclined steel pylon, which overlap at the centre of the river to form a 'structural handshake' - a powerful metaphor for reconciliation, drawing on inspiration from the nearby sculpture ‘Hands Across the Divide’ by Maurice Harron.

The bridge was funded by the EU's Peace III programme under the shared space initiative which supports projects that bring together communities that have been formerly divided.

EU Commissioner for Regional Policy Johannes Hahn cut the ribbon at the opening ceremony alongside First Minister Peter Robinson, Irish Republic premier Enda Kenny and Deputy First Minister Martin McGuinness.

Did you know …

There were no accidents during the construction of the bridge (it took 142,000 hours to build)
It weighs 1,000 tonnes and the heaviest section weighs 120 tonnes
Sections of the deck were lifted into place by a 500 tonne crane on the Forth Atlas floating barge

Difference the project has made

With over one million crossings within 14 months of opening, the Peace Bridge has become a focal point for city events as well as a valuable transport link, including New Year celebrations, the launch of City of Culture year and features in marketing campaigns and publications.

It also has its very own Royal Mail postage stamp.

The construction of the bridge had some immediate benefits for the local community with a job created for one longterm unemployed person for every £1m spent. This successful model of public/private sector collaboration is now being used on other projects in the city.

There were local community benefits for 39 schools and community groups who visited the site and learned about construction and environmental sustainability.

There were also events held during the construction including a sponsored zipwire across the River Foyle to raise money for local charity Foyle Search and Rescue. The construction team also sponsored a project to help monitor and protect the local red squirrel population in nearby woods.

How the bridge was built

The bridge is a unique design and the first of this type to be built in the UK. With the asymmetric elements like the curve of the bridge deck and the leaning towers, it was a challenge for the engineers to achieve a stable design.

The bridge is an unusual, curved, self-anchored suspension bridge with two inclined pylons (towers) dividing the structure into three continuous spans of 65m, 100m and 65m over the river.

The main structure is made up of a triangular closed cell steel girder with cantilever (beams fixed at one end) crossed girders on one side only. A perforated aluminium decking system spans transversely between the cross girders. The width of the bridge deck varies between 4m and 5.6m. The deck was constructed with weathering steel and painted white to meet the architect’s design.

The innovative arrangement of two overlapping girders in the middle of the span provides an adjustable air gap, which isolates each deck and makes the bridge more aerodynamically stable (allowing winds to pass over/through the structure with less effect).

Because of the complex curves of the bridge structure it was ‘put together’ in a different way to most bridges which are constructed incrementally. The whole of the Peace Bridge including its cables and hangers were pulled together in a single operation.

The complete length of the deck was placed on supports, initially set high, before installing all cables and hangers, and then the deck was lowered on synchronised jacks.

The engineers used pre-cast concrete shells ‘dropped in’ to support the piers as they were built and foundations piled. These were held above sea bed level before being sealed, dewatered and the inner core concreted.

The efficient design of these works reduced the amount of construction in the river and the impact on the environmentally sensitive area. The completed bridge received many awards including a special rating for sustainable and environmentally friendly construction.