Tower Bridge

• 1. Inception And Legislation

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  By the late 1870s, London's East End had swelled to include nearly 40% of the city's population. This demographic shift created an urgent need for a new river crossing downstream from the existing London Bridge. A traditional fixed bridge at street level was impossible because it would block sailing ships from reaching the Pool of London between the Tower and the old bridge. The Corporation of London formed a Special Bridge or Subway Committee in December 1875 to find a solution. More than fifty designs were submitted by engineers like Sir Joseph Bazalgette, yet all failed due to insufficient headroom for tall masts. It took until the 24th of July 1884, for a committee report to finally propose a mechanical opening bridge. On the 28th of October 1884, a proposal for Design C, a bascule bridge, reached the Court of Common Council. Parliament granted royal assent to the Corporation of London (Tower Bridge) Act on the 14th of August 1885. This legislation mandated specific dimensions: a central span of 200 feet clear width and a height of 135 feet above Trinity high water when open. The act also required the design to accord with the architecture of the nearby Tower of London. Construction was initially scheduled to be completed within four years.

• 2. Construction And Engineering

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  Work officially began on the 22nd of April 1886, with the foundation stone laid by the Prince of Wales on June 21. The project employed an average of 432 people daily, though over 1,200 workers participated throughout its eight-year duration. Eight separate contracts divided the labor among firms like John Jackson, Sir W. G. Armstrong, Mitchell, and Co., and Sir William Arrol & Co. The total accepted tender cost reached £830,005, eventually rising to £1,184,000. Two massive piers containing over 70,000 tons of concrete were sunk into the riverbed between September 1886 and January 1890. More than 11,000 tons of steel formed the framework for the towers and walkways. These structures were then clad in Cornish granite and Portland stone to harmonize with the Tower of London's Gothic style. Horace Jones died in 1887, leaving engineer John Wolfe Barry to take over as architect. Barry later credited Mr. Fyson, Mr. Stevenson, and Resident Engineer Edward Cruttwell for their vital contributions. Only ten fatal accidents occurred during construction: four while sinking foundations, one on the approaches, and five on the superstructure.

• 3. Operational Evolution

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  Tower Bridge officially opened on the 30th of June 1894, by the Prince and Princess of Wales. The original hydraulic system used pressurized water stored in six accumulators powered by stationary steam engines. This machinery was designed to be equal to twice the requirements of the Board of Trade. In 1972, the operating mechanism was converted to an electro-hydraulic system designed by Geoffrey Beresford Hartwell of BHA Cromwell House. Oil replaced water as the new hydraulic fluid, though the final pinions from the old system remained in use. A third engine, a 150 hp horizontal cross-compound built by Vickers Armstrong Ltd., was installed in 1942 as a wartime backup. This redundant engine became obsolete after the 1974 modernization and was donated to the Forncett Industrial Steam Museum. The high-level walkways were closed to pedestrians in 1910 due to safety concerns regarding prostitutes and pickpockets. They reopened in 1982 as part of the Tower Bridge Exhibition. Glass floors were added to the walkways in 2014 to allow visitors to look down at the road and river below.

• 4. War And Incidents

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  During World War II, Tower Bridge served as a major transport link to the Port of London and became a target for enemy action. On the 7th of September 1940, a direct hit on the high-level span severed the hydraulic mechanism and took the bridge out of action. An April 1941 parachute mine explosion caused serious damage to the bascules, towers, and engine room. In December 1952, a number 78 double-decker bus crossed the bridge while it was raising. Driver Albert Edward Gunter accelerated the vehicle to clear an 1.8-meter drop onto the north bascule before it could rise. Twelve passengers received minor injuries, but Gunter earned a £10 bonus for his quick thinking. On the 5th of August 1968, a Royal Air Force Hawker Hunter jet fighter flew unauthorized under the pedestrian walkway at an estimated altitude of 30 feet. The pilot was arrested upon landing and discharged from the RAF on medical grounds. A single-engined Beagle Pup was flown under the walkway by Peter Martin on the 31st of July 1973, before crashing in the Lake District two hours later.

• 5. Modern Maintenance And Tourism

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  In April 2008, authorities announced a £4 million refurbishment project scheduled to take four years. Contractors stripped existing paint down to bare metal and repainted the structure blue and white, restoring its original color scheme from 1977. Each section was enshrouded in scaffolding and plastic sheeting to prevent old paint from falling into the Thames. The renovation of the suspension chains used a state-of-the-art coating system requiring up to six layers of paint. In 2016, the bridge closed to all road traffic from October 1 to December 30 for structural maintenance on timber decking and waterproofing. Today, Tower Bridge handles over 40,000 crossings daily, including motorists, cyclists, and pedestrians. The Tower Bridge Exhibition charges an admission fee and houses displays inside the twin towers and Victorian engine rooms. In 2019, the attraction recorded 889,338 visitors, making it the 34th most visited attraction in England and the 17th most visited paid entry site.