Tower Bridge Overview
Tower Bridge, London’s iconic landmark, is a suspension bridge that crosses the River Thames. The bridge was constructed between 1886 and 1894 and opened to the public in 1894. It is located between the boroughs of Tower Hamlets and Southwark and is visited by millions of tourists every year. Tower Bridge is often mistaken as London Bridge, which is actually located a mile upstream.
The Need for a New Bridge
The increasing population and the growth of the Thames shipping industry in the 19th century created a need for a new river crossing. The existing London Bridge was inadequate for the increasing traffic, and therefore, a new bridge was required. In 1876, a committee was formed to address the issue. After several designs were rejected, the committee approved a design submitted by Sir Horace Jones, the City Architect. The design proposed a bridge with two towers and a central section that could be raised to allow ships to pass through.
Designing the Tower Bridge
Jones created a Gothic-inspired design that featured a hybrid of suspension and bascule bridge types. It was an innovative design that used modern materials and construction methods, while still retaining a traditional appearance. Jones collaborated with engineer John Wolfe Barry to bring the design to life. The design was approved in 1884, and work began in 1886.
The Bridge’s Foundations
The bridge’s foundations were laid by constructing two large caissons, or watertight chambers, on the riverbed. The caissons were then filled with concrete, and the towers were erected on them. The construction of the caissons was a challenging task, and workers had to use compressed air to work at depths of up to 80 feet below the riverbed.
Building the Towers
The towers of Tower Bridge were constructed using Cornish granite and Portland stone. The granite was used for the lower sections of the towers, while the upper sections were made of Portland stone. The towers were constructed using a mix of traditional and modern methods. The stone was cut and shaped by hand, while the steelwork was prefabricated and then bolted to the towers on-site.
The Steel Superstructure
The bridge’s steel superstructure was designed to be lightweight, yet strong enough to support the weight of the roadway and the traffic. The steel was sourced from several steelworks around the UK, and the parts were manufactured off-site and then assembled on-site. The steelwork was painted blue and gold, which became the bridge’s iconic color scheme.
The Materials for the Roadway
The roadway of Tower Bridge was designed to be a composite structure, consisting of timber and concrete. The timber decking was laid on top of a steel frame and then covered with a layer of concrete. The timber decking was replaced with a steel grating in the 1970s to reduce the weight on the bridge.
The Hydraulic System
The hydraulic system used to raise and lower the bridge was a sophisticated design that used pressurized water to power the machinery. The system was designed by engineer William Armstrong and used water from the London Hydraulic Power Company’s network. The system was in use until 1976, when it was replaced by an electric motor system.
The Walkways and Staircases
The walkways of Tower Bridge were designed to allow pedestrians to cross the bridge even when it was raised. The walkways are located on the outside of the towers and are accessed via staircases. The walkways offer stunning views of London and the River Thames.
The Tower Bridge’s Color Scheme
The blue and gold color scheme of Tower Bridge was chosen to complement the nearby Tower of London. The color scheme was not universally popular, and there were calls to paint the bridge in other colors. However, the color scheme has become an iconic part of the bridge’s identity.
Maintaining the Tower Bridge
Maintaining a bridge that is over 125 years old is a challenging task. The bridge is regularly inspected and maintained by a team of engineers and technicians. The steelwork is painted every few years to protect it from corrosion, and the hydraulic system is still used for testing purposes.
Conclusion: The Tower Bridge’s Legacy
Tower Bridge is an iconic landmark that has become a symbol of London. Its innovative design and use of modern materials have allowed it to stand the test of time. Tower Bridge is a testament to the ingenuity and skill of the Victorian engineers who designed and built it and remains a popular tourist attraction and a vital river crossing for Londoners.
