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,
London Bridge Rennie's son. Work began in 1824 and the foundation stone was laid, in the southern coffer dam, on 15 June 1825. The old bridge continued in use while the new bridge was being built, and was demolished after the latter opened in 1831. New approach roads had to be built, which cost three times as much as the bridge itself. The total costs, around £2.5 million (£ in ), were shared by the British Government and the Corporation of London. Rennie's bridge was long and wide, constructed from Haytor granite. The official opening took place on 1 August 1831; King