Constructing London’s Tower Bridge
In the late 1800s, London was faced with the task of building a new span across the Thames, downstream of London Bridge. In order to allow tall-masted sailing ships to pass through to the Thames’ port facilities, the new bridge could not be a typical street-level, fixed crossing.
In 1877, a committee was formed which held a public competition for a bridge design. After a contentious few years, the committee settled on the design of City Architect (and committee judge) Sir Horace Jones.
Jones’ design was a hybrid, with two suspension bridge spans reaching from the river banks to two towers in the middle of the river. The towers were connected by elevated walkways and a bascule bridge (more commonly known as a drawbridge) that could hydraulically raise to allow ships to pass.
The eight-year process of construction began in 1887 with the sinking of the two tower piers, which contained more than 70,000 tons of concrete.
Atop these piers, the steel framework of the towers was put into place. This framework was initially planned to be covered in brick, but when George D. Stevenson took over the project, he decided to give the towers an elaborate Victorian Gothic facade of granite and limestone, to better match the nearby Tower of London.
The two movable bascules were driven by steam-powered hydraulics, which could raise the leaves of the bridge to a maximum angle of 86 degrees within a minute.
On June 30, 1894, the bridge was officially opened to the public by the prince and princess of Wales.
The elevated walkways were initially meant to allow pedestrians to cross when the bridge was raised, but because they were only accessible by several flights of stairs, they were rarely used and closed in 1910.