Catherine worked on the project from the initial competition stage, which was anonymous and of international interest with over 200 entries, and on through the full design and construction phases to include the remedial damping work.
Linking the borough of Southwark Council to the Corporation of London over the Thames and in the shadow of St Pauls Cathedral created a very complex and lengthy approvals process which required multiple planning applications and extensive consultation with over 100 interested parties. Catherine steered the project and its developing design through this period culminating in a special meeting of the Court of Common Council for final approval.
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 on to the cables at 8-metre intervals to support the deck itself. The very shallow structure means that the cables never rise more than 2.3 metres above the deck, allowing those crossing the bridge to enjoy uninterrupted panoramic views 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. .
The bridge initially opened in June 2000 with over 100,000 people crossing it during the first weekend. However this very heavy pedestrian traffic caused the bridge to exhibit greater than expected lateral movement which led to a temporary closure. Extensive research followed which showed this movement to be caused by synchronised pedestrian footfall − a little known phenomena in the engineering world. The solution, to fit dampers discreetly beneath the deck and linking into the Y-supports, has proven highly successful with the associated research resulting in changes to the codes for bridge building worldwide.
Millennium Bridge Trust
Foster and Partners
Sir Anthony Caro
Image Credits: Foster and Partners