How long did it take to build the millennium bridge?

Answer 1

Construction began in late 1998 with the main works beginning on April 28, 1999 by Monberg Thorsen and McAlpine. The bridge was completed at a cost of £18.2m (£2.2m over budget) and opened on June 10, 2000 (2 months late) but unexpected lateral vibration (resonant structural response) caused the bridge to be closed on June 12 for modifications. The movements were produced by the sheer numbers of pedestrians (90,000 users in the first day, with up to 2,000 on the bridge at any one time). The bridge was on the route of a major charity walk and it was an exceptionally fine day. The initial small vibrations encouraged (or even obliged) the users to walk in synchronisation with the sway, increasing the effect even when the bridge was comparatively lightly loaded at the beginning of the day. This swaying motion earned it the nickname the Wobbly Bridge.

Attempts were made to limit the number of people crossing the bridge: this led to long queues, but dampened neither public enthusiasm for what was something of a white-knuckle ride, nor the vibrations themselves. The closure of the bridge only three days after opening attracted public criticism, as another high-profile British millennium project suffered an embarrassing setback, akin to how many saw the Millennium Dome.

Resonant vibrational modes have been well understood in bridge designs following the failure of the Tacoma Narrows Bridge. However this was the first time a bridge had displayed this type of pedestrian excited lateral motion. This motion was caused by the human reaction to small lateral movements in the bridge, which set up a driven harmonic motion in the bridge. As such the motion was not anticipated by the computational analysis of the bridge prior to construction. It is often thought that the unusually low profile of the suspension cables contributed to the problem, but an analysis by the structural engineer, Arup, shows that it can occur in any suspension bridge which happens to have the appropriate resonant frequencies. After extensive analysis, the problem was fixed by the retrofitting of 37 fluid-viscous dampers (energy dissipating) to control horizontal movement and 52 tuned mass dampers (inertial) to control vertical movement. This took from May 2001 to January 2002 and cost £5m. After a period of testing the bridge was successfully re-opened on 22 February 2002, and as yet there have not been any noticeable severe vibrations

Answer 2

According to wikipedia, Construction began in late 1998 with the main works beginning on April 28, 1999 by Monberg Thorsen and McAlpine. The bridge was completed at a cost of £18.2m (£2.2m over budget) and opened on June 10, 2000 (2 months late) but unexpected lateral vibration (resonant structural response) caused the bridge to be closed on June 12 for modifications. After a period of testing the bridge was successfully re-opened on 22 February 2002, and as yet there have not been any noticeable severe vibrations.

Answer 3

2 years

Answer 4

London bridge now is living in Arizona.An American consortium offered it ,thinking they have been procuring Tower Bridge.additionally,no bridge around the Thames ever value a penny in public funds or taxes,through a fund set up approximately 500 years in the past.

Answer 5

dunno but i recon it took a week for the guy b4 me 2 answer