Millennium Bridge, London people walking caused small sideways oscillations in the bridge, which in turn caused people on the bridge to sway in step, increasing the amplitude of the bridge oscillations and continually reinforcing the effect. On the day of opening, the bridge was crossed by 90,000 people, with up to 2,000 on the bridge at any one time. Resonant vibrational modes due to vertical loads (such as trains, traffic, pedestrians) and wind loads are well understood in bridge design. In the case of the Millennium Bridge, because the lateral motion caused the pedestrians loading the bridge to directly participate with the bridge,
Albert Bridge, London in 1957 the London County Council proposed replacing Albert Bridge with a more conventional design. A protest campaign led by John Betjeman resulted in the withdrawal of the proposal, but serious concerns about the integrity of the bridge continued. In 1964 an experimental tidal flow scheme was introduced, in which only northbound traffic was permitted to use the bridge in the mornings and southbound traffic in the evenings. The bridge's condition continued to deteriorate however, and in 1970 the Greater London Council (GLC) sought and obtained consent to carry out strengthening work. In April 1972 the bridge was closed for