When the bridge first opened in 2000, pedestrians walking in step with each other caused vertical oscillations with an amplitude up to 1 in (25 mm). Although this did not pose any danger of structural damage or collapse this effect was disconcerting to pedestrians; the lateral swaying, though smaller in amplitude (about 0.25 in or 6 mm), was far more visible. The bridge was closed, and fitted with dampers to increase its dynamic rigidity by over tenfold without sacrificing much comfort by its engineers Ove Arup.
