Tower Bridge, the iconic bascule bridge over the River Thames, gets its name from the nearby
Tower of London. Today it is owned and maintained by Bridge House Estates, a charitable trust overseen by the Corporation of London.
In the second half of the 19th century, increased commercial development in the East End necessitated a new river crossing downstream of London Bridge. A traditional fixed bridge couldn't be without cuting off access to the port facilities in the Pool of London. A tunnel beneath the Thames, the
Tower Subway, was opened in 1870, but only accommodated pedestrian traffic. In 1876, A Special Bridge or Subway Committee was formed to oversee public design competition that attracted over 50 submissions, including one from civil engineer Sir Joseph Bazalgette. It was not until 1884 that a design submitted by Horace Jones, the City Architect, was approved.
Jones' design was for a bascule bridge, 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. Although each bascule weighs over 1,000 tons, they are counterbalanced to allow raising in one minute. The original hydraulic raising mechanism was powered by pressurized water stored in six accumulators. Water was pumped into the accumulators by steam engines. Today the original hydraulic machinery still opens the bridge, but it has been converted to oil and electric motors have replaced the steam engines.
Construction of the bridge started in 1886 and took 8 years, employing 5 major contractors and 432 construction workers. Two massive piers, containing over 70,000 tons of concrete, were sunk into the river bed to support 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 his chief engineer, Sir John Wolfe-Barry, took over the project. Wolfe-Berry replaced Jones' original mediaeval style facade with the distinctive landmark, ornate Victorian gothic style.
The bridge was
opened on June 30, 1894 by the Prince of Wales, the future King Edward VII, and his wife, Alexandra of Denmark, effectively replacing the Tower Subway, 400 m to the west, the world's first underground tube railway. It closed a few years later.
The
high-level walkways between the towers became a haunt for prostitutes and pick-pockets, and were closed in 1910. They were reopened as part of the Tower Bridge Experience, an exhibition mostly housed in the bridge's twin towers. The Experience also affords access to the original steam engines, housed in a building close on the south end.
Although river traffic is now a fraction of what it used to be, it still takes priority over road traffic. This nearly caused a diplomatic incident in 1996, when the motorcade of United States President Bill Clinton got stuck on Tower Bridge while the bascules were unexpectedly opened.
