Question

had to be closed after just a few days after its opening. а)The Tower Bridge b)The Westminster Bridge c)The Millennium Bridge​

Answer 1

The Millennium Bridge.
The bridge opened on 10 June 2000, one month late. Unexpected lateral vibration due to resonant structural response caused the bridge to be closed on 12 June for modifications.

Answer 2

The correct answer is c) The Millennium Bridge.

The Millennium Bridge, located in London, is a pedestrian suspension bridge spanning the River Thames. It was officially opened on June 10, 2000, as part of the Millennium celebrations. However, due to unexpected swaying and wobbling motion experienced by pedestrians, the bridge had to be closed for modifications just a few days after its opening.

The lateral movement of the bridge was caused by a phenomenon known as synchronous lateral excitation, where the natural sway of pedestrians on the bridge coincided with the bridge's natural frequency. This caused the bridge to sway excessively, leading to concerns about its structural integrity and safety.

After extensive modifications and engineering solutions, including the installation of dampers and additional lateral supports, the Millennium Bridge was reopened to the public in 2002. It has since become a popular attraction and an iconic landmark in London.