Architect:
Foster and Partners - Londen.
Constructeur:
Arup - Londen.
The Millennium Bridge springs from a creative collaboration between architecture, art and engineering. Developed with sculptor Anthony Caro and engineers Arup, the commission resulted from an international competition. Londons only pedestrian bridge and the first new Thames crossing since Tower Bridge in 1894, it links the City and St Pauls Cathedral to the north with the Globe Theatre and Tate Modern on Bankside. A key element in Londons pedestrian infrastructure, it has created new routes into Southwark and encouraged new life on the embankment alongside St Pauls.
Structurally, the bridge pushes the boundaries of technology. Spanning 320 metres, it is a very shallow suspension bridge. Two Y-shaped armatures support eight cables that run along the sides of the 4-metre-wide deck, while steel transverse arms clamp onto the cables at 8-metre intervals to support the deck itself. This groundbreaking structure means that the cables never rise more than 2.3 metres above the deck, allowing pedestrians uninterrupted panoramic views of London and preserving sight lines from the surrounding buildings. As a result, the bridge has a uniquely thin profile, forming a slender arc across the water, and spanning the greatest possible distance with the minimum means. A thin ribbon of steel by day, it is illuminated to form a glowing blade of light at night.
The bridge opened in June 2000 and an astonishing 100,000 people crossed it during the first weekend. However, under this heavy traffic the bridge exhibited greater than expected lateral movement, and as a result it was temporarily closed. Extensive research and testing revealed that this movement was caused by synchronised pedestrian footfall - a phenomenon of which little was previously known in the engineering world. The solution was to fit dampers discreetly beneath the deck to mitigate movement. This proved highly successful and the research undertaken by the engineers has resulted in changes to the codes for bridge building worldwide.
