Презентация на тему: Tower Bridge

Tower Bridge

History Background In the second half of the 19th century, increased commercial development in the East End of London led to a requirement for a new river crossing downstream of London Bridge. A traditional fixed bridge could not be built because it would cut off access to the port facilities in the Pool of London, between London Bridge and the Tower of London.

Construction Tower Bridge under construction, 1892Construction started in 1886 and took eight years with five major contractors – Sir John Jackson (foundations), Baron Armstrong (hydraulics), William Webster, Sir H.H. Bartlett, and Sir William Arrol & Co.– and employed 432 construction workers. E W Crutwell was the resident engineer for the construction.Two massive piers, containing over 70,000 tons of concrete, were sunk into the riverbed 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 pleasing appearance.Jones died in 1887 and George D. Stevenson took over the project. Stevenson replaced Jones' original brick facade with the more ornate Victorian Gothic style, which makes the bridge a distinctive landmark, and was intended to harmonise the bridge with the nearby Tower of London.The total cost of construction was £1,184,000 (£100 million as of 2010).

Opening The bridge was officially opened on 30 June 1894 by The Prince of Wales (the future King Edward VII), and his wife, The Princess of Wales (Alexandra of Denmark).The bridge connected Iron Gate, on the north bank of the river, with Horselydown Lane, on the south – now known as Tower Bridge Approach and Tower Bridge Road, respectively.Until the bridge was opened, the Tower Subway – 400 m to the west – was the shortest way to cross the river from Tower Hill to Tooley Street in Southwark. Opened in 1870, Tower Subway was the world's first underground ('tube') railway, but closed after just three months and was re-opened as a pedestrian foot tunnel. Tower Bridge is one of five London bridges now owned and maintained by the Bridge House Estates, a charitable trust overseen by the City of London Corporation.

Design The bridge is 800 feet (244 m) in length with two towers each 213 feet (65 m) high, built on piers. The central span of 200 feet (61 m) between the towers is split into two equal bascules or leaves, which can be raised to an angle of 83 degrees to allow river traffic to pass. The bascules, weighing over 1,000 tons each, are counterbalanced to minimize the force required and allow raising in five minutes.The two side-spans are suspension bridges, each 270 feet (82 m) long, with the suspension rods anchored both at the abutments and through rods contained within the bridge's upper walkways. The pedestrian walkways are 143 feet (44 m) above the river at high tide.

Facts " 1912 - Frenku Makklinu (Frank McClean) happened to staired between stairwell and passage high level bridge on its biplane to avoid the accident. " 1952 - once upon a time bridge have unexpectedly begun to divorce, and london bus, found on bridge, was have to make 'jump with one stairwell on another. " 1977 - a bridge was painted in red, white and blue colour in commemoration jubilee Queens (before this he was painted in chocolate color).

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