Engineering: The Eiffel Tower in Paris

Radio mast, monument, tourist magnet: the Eiffel Tower is one of the most famous buildings in the world. It is one of the symbols of France and a figurehead for loyalty, love, and freedom. The tower was inaugurated on March 31, 1889. But architectural hurdles had to be overcome during its construction.

The erection of the Eiffel Tower in Paris took a good two years. The construction phase began at the beginning of 1887 and ended in March 1889. It served as the entrance portal and viewing platform for the World’s Fair on the 100th anniversary of the French Revolution. The Eiffel Tower originally towered 312 meters high and was named after its designer, the engineer Alexandre Gustave Eiffel. There was great resistance among artists and scholars to the construction of the building. They protested by putting their displeasure on paper and among the population. The Eiffel Tower alone would tower over the city as a bearer of thoughtless European and American art and thus overshadow the architecture of Paris. It should take a while.

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A temporary structure of superlatives

Originally, the colossus was supposed to shape the image of Paris for only twenty years before it was dismantled into its parts, then dismantled. The tower did not only gain historical relevance for the French, as it was used for radio and later also as a military telecommunications base during the First World War. From 1921, the whole of Europe benefited from the Eiffel Tower as an important cornerstone for public broadcasting.

Until the completion of the Chrysler Building in New York, the Eiffel Tower was even considered the tallest building in the world until 1930.

In 1935, the first French television channel Télévision Française 1 began its activity. At the time, this was the most powerful transmitter in the world with an output of 30 kW and was transmitted to domestic televisions via the Eiffel Tower. It is still used today as the most important broadcasting center in the greater Paris area. In the upper part of the building, there is also the Michelin-starred tower restaurant “Le Jules Verne”.

Icon of architecture

Alexandre Gustave Eiffel, the designer of the Dame de Fer Tour de Eiffel, was born in Dijon on December 15, 1832, and died in Paris on December 27, 1923. As an engineer, architect, and namesake, he played a key role in the construction of what is now the iconic symbol of Paris. A previous important project by Eiffel was, for example, the role of chief engineer in the construction of the 500-meter-long railway bridge over the Garonne in Bordeaux, which was christened Passerelle Eiffel in 1858.

Despite the later independence in various construction projects, which were primarily limited to the construction of railway lines and bridges, Eiffel applied for a patent on September 18, 1884. This should be decisive for the later construction of the Eiffel Tower. It was a novel process with which metal pillars and pylons could be built at a height that far exceeded the previous 300-meter mark. Eiffel discussed this in a lecture to the Société des Ingénieurs civils on March 30, 1885. In concrete terms, this means that Eiffel made use of the physics of wind strength to redirect the enormous forces to the internal construction.

Engineering in the age of industrialization

Just as skyscrapers in earthquake regions have various spring constructions, the Eiffel Tower also dissipates any stresses that occur in the ground. This reduces the load on the outer bars. The well-thought-out and seemingly complicated architecture is so simple that it can be seen as a stroke of genius. Sixteen vertically offset iron struts grouped together in groups of four protrude into the sky in an arch shape and are connected by the three visitor platforms. The main struts combine to form a pylon above the second platform. The statically important platforms or horizontal connections are each at a height of around 57, 115, and 276 meters. A total of over 2.5 million riveted connections were required for the construction. 000 individual elements hold together. The individual foundations of the feet are below the level of the Seine, which means that watertight metal cladding filled with compressed air is necessary for the construction, which pushes back the groundwater.

Orientation and practical use

The ground plan of the landmark is square, with the pillars spaced exactly 74.24 meters apart. Overall, this results in a spread of 124.9 meters. The pillars are also precisely aligned with the cardinal points, with the north and west pillars facing the Seine, while the east and south pillars point towards the Champ de Mars. The pillars are also home to the ticket offices, access to the lifts and stairs to the visitor platforms, and the tower restaurant.

Since the original construction in 2001, an antenna has been installed at the top of the structure so that it can also be used as a control center for digital television. Sometimes the Eiffel Tower remains so at a total height of 324 meters. However, there are seasonal variations here due to the expansion of the metal braces. Between summer and winter, the total height of the lattice tower can fluctuate by around 30 centimeters.

Start of a series of replicas

The construction of the Iron Lady triggered a true tower-building euphoria worldwide. What was initially considered a controversial building quickly gained global prominence? The Eiffel Tower serves as a model and pioneer structure for the steel revolution around the world – even if the colossus is made of iron.

Especially during the colonial period, many other powers enjoyed the outstanding architecture of the Eiffel Tower. One of the first replicas was the Blackpool Tower (Blackpool, England), which was built between 1891 and 1894. It is 158.1 meters high and, despite its obvious reference and adaptation of individual building elements to the Paris Eiffel Tower, counts as an architecturally successful. It was even included in the monument protection with the highest classification. Particularly interesting about Blackpool Tower is the Victorian-style style and the accommodation of several renowned attractions such as a circus. After an extensive restoration, it is still today a crowd puller and absolute must-see sightseeing in the north-west of England.

However, there were other successful replicas that, like the Blackpool Tower, gained in popularity and importance. In January 1890, a 60-meter-high ice replica was on display in St. Petersburg. A year later, the Petřín lookout tower was built in Prague for an industrial exhibition – it also measures 60 meters. Even in France, the model of the iron lady was emulated again and again.

Stories of unsuccessful replicas

The New Brighton Tower (Wallasey, England) is less successful but still worth mentioning. In 1886 construction began on the 172.8-meter high tower. Due to poor quality building material and little popularity from construction companies and the population, the unfinished structure had to be removed again in the 1920s. The tower was never completed and was considered a failure despite its similarity to the Eiffel Tower.

Many more of these unsuccessful attempts to replicate followed, including a project in the middle of London. The then designer and planner Sir Edward Watkin tried in 1890 to win Gustave Eiffel himself as an engineer for the Watkin Tower, which was planned to be around 358 meters high. However, Eiffel refused for patriotic reasons and the construction project had to be canceled in 1907 after the erection of a 47-meter high tower stump.

The Eiffel Tower today

With around 7 million paying visitors per year, the tower now makes a major contribution to the tourism industry. Visitors can not only visit the Le Jules Verne restaurant here but also enjoy a panoramic view of Paris from high above. However, the Eiffel Tower not only impresses with its imposing height or the multitude of employment and usage opportunities that it offers its visitors all year round and almost continuously. It is considered an icon of architecture and engineering and is constantly being equipped with the latest technological advances. The Parisian landmark has even been a listed building since 1964 and in 1986 the American Society of Civil Engineers added it to the list of historic milestones in engineering.

The landmark turns green

The operation of the Eiffel Tower, which runs 365 days a year, naturally incurs costs. Maintenance and power consumption are particularly important. The elevators alone cover around 100,000 km in one year. The total electricity consumption is around 680,000 kWh per year. On the occasion of this number, the operators of the Iron Lady decided in 2015 to “let the tower go green”. At a height of 127 meters, the New York company Urban Green Energy (UEG) installed two VisionAIR5 wind turbines, which are supposed to compensate for at least a small part of the energy required, namely around 10,000 kWh per year. According to the company, they can already generate energy for the first visitor platform, which includes space, attractions, and the tower restaurant for 3,000 visitors.

Further developments

Construction work began in January 2020 to redesign the access routes – primarily the Paulhan and Refuznik paths. The primary goals of this renovation include redesigning the entrance areas of the Eiffel Tower as well as revising the flora around this area. This should increase the life expectancy of the plants that have settled there by 15 years and make the area more inviting for visitors. The construction work, which will be carried out gradually, should be finished before the beginning of summer, according to the company.

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