Architecture of Tower Bridge
Tower Bridge is one of Britain’s most recognisable, iconic landmarks, but it was actually designed purely as a functional bridge. In the mid-1800s, lots of road traffic needed to cross the River Thames downstream of London Bridge. A traditional bridge, however, would not allow river traffic to access the Pool of London docks.
The solution was a combined suspension and bascule bridge (also known as a drawbridge). Powered by hydraulics, bascules rise in order to allow boats to pass through. Designed by architect Horace Jones and civil engineer John Wolfe Barry (a son of Charles Barry, one of the architects of the Houses of Parliament), Tower Bridge was completed in 1894.
Construction & How the Bridge Works
Construction of Tower Bridge took 8 years, 5 contractors and 432 workers. More than 11,000 tons of steel provided the framework for the towers and walkways, although the framework itself is clad in granite and stone so as to protect the steel and offer a nicer appearance.
One of the most spectacular feats of civil engineering in Victorian Britain, Tower Bridge is 240m in length with two towers at 65m high. The central span between the towers is split into two equal bascules, which rise to an 86-degree angle, thus allowing river traffic to pass. Each bascule weighs over 1,000 tons and is counterbalanced so can rise in about five minutes. A high-level walkway was originally designed for members of the public to use to walk across the bridge while the bascules were raised for boats. It was closed in 1910, however, because people preferred to wait at street level than climb the stairs with heavy belongings!
The original hydraulic operating mechanism was powered by steam, but in 1974 it was replaced by an electro-hydraulic system, using oil and electricity instead of water.
Tower Bridge with the bridge raised, by Rob Bye
Tower Bridge Today
Tower Bridge is in continuous use. According to TowerBridge.org.uk, the City of London Corporation must raise the Bridge to provide access ‘for registered vessels with a mast or superstructure of 30 feet or more’. Bridge-lifting is free of charge subject to 24 hours’ notice and is available anytime and on any day. In total, Tower Bridge is raised about 850 times per year!
In 1982 a permanent exhibition opened at the Tower and the walkways reopened, transforming Tower Bridge into a tourist attraction with spectacular panoramic views of London. Nowadays visitors enjoy regular behind-the-scenes tours; the original steam engines remain in the Victorian Engine Rooms for public viewing and there is a glass floor in the walkways offering birdseye views of bascules below.
Despite its status as an international tourist attraction, Tower Bridge hosts everyday events for locals such as sunrise yoga classes on the glass walkway. Furthermore, it works with local communities, has an artist in residence and even boasts a ground level ‘walk of fame’.
Are you interested in learning more about Tower Bridge? Visit its official website for more facts and figures, plus information about visiting in person. Do you have any interesting facts we’ve missed out? Let us know in the comments or on social media!
An illustration of Tower Bridge