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,
Kingston Bridge, London a problem and in 1911 the engineering firm Mott & Hay was contracted to widen the bridge on the downstream side. The work was undertaken between 1912 and 1914 with the carriageway increased from 25 feet to 55 feet. A new façade of Portland Stone was designed to replicate the features of the original. The bridge was reopened in October 1914. It was widened again in 2000 to include two bicycle lanes, larger pavements and a bus lane, from 55 feet to 79 feet. The bridge was given protection as a Grade II* listed structure in 1951. Kingston Bridge, London