Another notable and iconic landmark, the Tower Bridge, was officially opened on this day in 1894. It is a remarkable piece of engineering and had withstood the test of time – a snapshot of a bygone era when, y’know, we built things that didn’t break down after a decade or so…
An Iconic Feature
London is a city of many bridges, with multiple crossings over the mighty Thames River. However, as a crucial waterway, the need for practical crossings in the late 19th century was of paramount importance.
During pre-construction consultations, it was agreed that a traditional fixed crossing at street level would prevent access by sailing ships to the Port of London. As such, in 1877 a special committee was formed and chaired by Sir Albert Joseph Altman to find a solution to this problem.
With over 50 designs submitted to the committee, they weren’t without choice during this planning process. In 1884 it was decided that a bascule bridge – basically a drawbridge – would span the river. Sir John Wolfe Barry was appointed as the engineer, with renowned architect Sir Horace Jones also brought onboard.
One year later in 1885, an Act of Parliament was passed and the bridge’s construction would soon be underway. There were certain specifications that had to be met, however. The opening span was required to give a clear width of 220 feet and a headroom of 135 feet. Additionally, the construction had to be in a Gothic style.
Sir Barry gave life to the iconic design with two bridge towers built on piers. The central span of the bridge was split into two equal bascules or leaves, which could then be raised to allow vital river traffic to pass through.
The two side-spans were suspension bridges, with the suspension rods anchored at the abutments and through rods found within the bridge’s upper walkways. The design of this bridge is not only iconic but highly innovative.
Construction of the bridge started in 1886 and took over eight years to build. The scale of this construction project is quite remarkable when looking at the numbers involved.
Five major contractors played a role in the construction of the bridge, along with over 400 workers.
- The Tower Bridge under construction (1892)
During the construction process, two enormous piers containing over 70,000 tons of concrete were sunk into the Thames riverbed. Over 11,000 tons of steel provided the framework for the sturdy towers and walkways. The steel was protected by a Cornish granite and Portland stone cladding, which played a crucial role in the upkeep of the structure.
Not only did it protect the underlying steelwork from the elements, it also gave the bridge a pleasing aesthetic.
This cladding was replaced, however, when George D. Stevenson took over the project. Stevenson replaced the original brick facade with a more ornate Gothic style – which also reflected the style of the nearby Tower of London. It is this style that we all know today and what makes it one of the most iconic landmarks in London.
Powering the Bridge
The bridge used some of the most cutting-edge technology available at the time. The original raising mechanism for the bridge was powered by pressurised water stored in a number of hydraulic accumulators.
Designed by Hamilton Owen Rendel, water was pumped into the accumulators by two horizontal twin tandem steam engines. The entire system along with the gas lighting was installed by well-known Westminster gas engineers, William Sugg & Co. The original gas lighting – open flame burners – was replaced with an incandescent system shortly after the bridge’s construction.
The original operating mechanism was replaced in 1974 with an electro-hydraulic drive system. Some of the original machinery has been retained and now resides in the old engine rooms on the south side of the bridge.
Quite A Bargain
Any Briton today will likely have their thoughts on construction projects and the often inflated costs surrounding them. It’s probably one of the main topics Brits moan about.
“That’s going to cost how much? You’ve got to be joking me…”
This was a project of monumental proportions for the time, costing a staggering £1,184,000 – that’s well over £120 million in today’s sterling. All things considered, that doesn’t seem too bad given how long the bridge has remained operational.
Here’s hoping the Tower Bridge will stand for another 120+ years, captivating future generations.