Millennium Bridge, London
In the year 2000, it should be possible to cross the Thames comfortably on foot from St Paul’s Cathedral to the new Tate Gallery on the south bank in only five minutes. By that time, the Millennium Bridge will link the City with the south side of the river at a point between the gallery and the Globe Theatre. The structure is conceived as a 370-metre-long suspension bridge hovering lightly over the Thames. Various materials and structural systems were explored in order to achieve a slender, light appearance. The outcome is a simple system, comprising two elliptical concrete piers 144 metres apart anchored in the bed of the river, and four cables, from which the walkway is suspended. Supported by two arms on each of the piers, the cables are spanned so tautly between the abutments on the banks that they sag by only 2.3 metres in the middle. Alone the great dead load of the cables and piers on the unstable clay bed of the Thames will result in settlement of the structure. Provision is therefore made for a subsequent adjustment of the cable tensioning. The pier dimensions reflect not only the dead and imposed loads on the bridge, but the current of the river and possible ship collisions as well.