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 but the octagonal tollbooths were left in place, and today are the only surviving bridge tollbooths in London. In 1884 the Board of Works' Chief Engineer Sir Joseph Bazalgette conducted an inspection of the bridge and found that the iron rods were already showing serious signs of corrosion. Over the next three years the staying rods were augmented with steel chains, giving it an appearance more closely resembling a conventional suspension bridge, and a new timber deck was laid, at a total cost of £25,000 (about £ in 2019). Despite these improvements, Bazalgette was still concerned about its structural integrity