TOWER BRIDGE(타워 브리지)

TOWER BRIDGE, LONDON, ENGLAND

How a Design was Chosen
The big problem for the Corporation of London was how to build a bridge downstream from London Bridge without disrupting river traffic activities. To get as many ideas as possible, the "Special Bridge or Subway Committee" was formed in 1876, and opened the design of the new crossing to public competition.
Over 50 designs were put forward for consideration, some of which you can see if you visit The Tower Bridge Exhibition. However, it wasn't until October 1884 that Horace Jones, the City Architect, in collaboration with John Wolfe Barry, offered the chosen design for Tower Bridge as a solution.

The Building of the Bridge
It took 8 years, 5 major contractors and the relentless labour of 432 construction workers to build Tower Bridge.
Two massive piers had to be sunk into the river bed to support the construction, over 11,000 tons of steel provided the framework for the towers and walkways. This was then clad in Cornish granite and Portland stone, both to protect the underlying steelwork and to give the bridge a more pleasing appearance.

How it Works - Then & Now
When it was built, Tower Bridge was the largest and most sophisticated bascule bridge ever built ("bascule" comes from the French for "see-saw"). It was a hydraulically operated bridge, using steam to power the enormous pumping engines. The energy created was then stored in six massive accumulators so that, as soon as power was required to lift the bridge, it was readily available. The accumulators fed the driving engines, which drove the bascules up and down. Despite the complexity of the system, the bascules only took about a minute to raise to their maximum 86 degrees.
Nowadays, the bascules are still operated by hydraulic power, but since 1976 they have been driven by oil and electricity rather than steam. The original pumping engines, accumulators and boilers are on show as part of The Tower Bridge Exhibition