You may recall seeing this video when I posted it back in 2011, http://highriser.blogspot.com.au/2011/10/wild-ride.html Unfortunately the video I embedded has been removed. But nothing ever disappears on the internet. You can see it here or just search You Tube for Tacoma Narrows Bridge. It is quite dramatic footage. It was about 1940 when it collapsed. Some 70 years later, engineering standards and understanding of forces are much better, but were they when London's Millennium Bridge was built, a mere 14 years ago? It seems not.
The footbridge crosses River Thames between Blackfriars rail bridge and Southwark Bridge, effectively linking St Pauls to the Tate Modern. Its construction began in 1998 for a 2000 opening and what a swaying disaster to London pride it turned out to be. It was closed later on the day of its opening, reopened the next day to restricted numbers, and then closed.
An extra £5 million and two years later it reopened and has never swayed again, yet still retains its nickname among some Londoner's of the Wobbly Bridge. I am not going into the technical reasons of why it wobbled because it is very much tech talk, but how about a video?