Building the Eiffel Tower

The Eiffel Tower was built in a two year period starting in 1887 and finishing in 1889. It was the first of its kind, built entirely of iron and completed in an amazingly short period of time due to several innovations implemented by its project manager, and manufacturer, Gustave Eiffel. The tower was actually designed by its architect, Stephen Sauvestre but was named after Eiffel and for good reason. Eiffel was not only the project manager; he was also its sponsor. Eiffel was a mechanical engineer whose success at his profession enabled him to start his own iron manufacturing company. Although the tower had its own architect and engineers, they all worked for Eiffel and Eiffel managed the project from start to finish.

Background

Gustave Eiffel began his career as a mechanical engineer. He got his started supervising work on an iron railway bridge connecting Montreal island to the mainland. He began his own business as a "constructor” manufacturing iron for various structural projects in factory on the outskirts of Paris. At this time iron was widely used in the construction of bridges but not in building construction. Eiffel broke new ground when he built the Statue of Liberty structure from iron (F. A. Bartholdi was responsible for forming the statue, Eiffel built the structure it rests on). He added to his reputation by constructing the dome for the Nice observatory from iron. He was also the constructor of the railway station in Budapest, Hungary.

The Challenge

An engineer (Maurice Koechlin), who helped Eiffel on one of the bridge contracts that Eiffel completed, encouraged Eiffel to submit a proposal for the Universal Exhibition of 1889 to be held in Paris. His idea for the bid was a 300 meter tower made of iron which would be the tallest structure in the world. The goal was to build a tower 1000 feet in height. Eiffel based his design on the way he had engineered bridge supports. The difference was the bridge supports were short relative to a 300 meter structure and were intended to bear a horizontal load rather than a vertical one.

The design called for 4 columns built of iron lattice work, joined by girders at intervals and coming together at the top. The columns were designed to angle outwards from the top down, starting in a vertical line at the top of the tower with the outwards angle increasing as the column approached the base. This gives the tower the classic shape that is recognized world wide but was originally intended to offer the minimum wind resistance.

Eiffel originally submitted his design (the design was actually authored by two designers who worked for Eiffel) to the city of Barcelona for the Universal Exposition of 1888 but was rejected as too off-beat. He submitted the design to the city of Paris where the Exposition was to be held in 1889 and this time approval was given for building his design on the Champs de Mars as the entrance to the exposition. This Exposition had historical significance because it was the centenary of the French Revolution. Eiffel did not receive approval to begin his project until

Eiffel’s design met with some fierce resistance from the artistic and architectural community in Paris. The artistic set protested on aesthetic grounds while one would suspect that at least some of the architects may have had an ulterior motive. A leading Paris newspaper, Le Temps, published an open letter from this group in which they called it the "Tower of Babel” and further referred to it as "useless and monstrous”. The letter asked the readership of Le Temps "Will the city of Paris continue to be associated with the strange and venal imaginations of a machine-maker, bringing upon itself dishonour and an ugliness that can never be corrected?” The addressee for the open letter was the Paris commission responsible for hosting the Exposition. As if resistance from the artistic crowd weren’t enough, Eiffel also faced critics who accused him of sacrificing engineering considerations for aesthetics!

Eiffel fought tooth and nail to preserve his project against these new stakeholders. He published a response in which he asserted that engineering practicality and aesthetics were not mutually exclusive and that the tower would be a handsome attraction that would enhance the beauty of Paris, rather than detract from it. He compared his design to the pyramids. He claimed that the tower would elicit exactly the same awed reaction that the pyramids of Egypt due to its size and form. His defense was successful; he continued to enjoy the support of the Exposition commissioners.

Eiffel had serious technical challenges to overcome to implement his design. Because of the height of the tower, high winds could work on the structure and cause structural damage or even collapse. The effect of the wind would have to be mitigated in some way. The intended purpose of the tower was a tourist attraction for the Exhibition and to that end restaurants were planned for the first and second levels. The problem was how to get the tourists up the curved columns of the tower to the restaurants.

The final challenge was the schedule. Eiffel received final approval for his project at the end of 1886 and couldn’t begin work until January of 1887 but the entire project had to be completed in time for the opening of the Exhibition on May 6, 1889.

The Construction Project

Work started on the cement pads which support each of the tower columns on January 26, 1887. The Champs de Mars runs close to the Seine River where the tower is situated and since the tower straddles the street, 2 of the pads had to be formed below the water line. The 2 pads on the side of the street opposite the Seine were simple enough to form but the 2 on the Seine side required the pads to be formed underwater. Fortunately for Eiffel, the Roeblings had solved this engineering problem during the construction of the Brooklyn Bridge 17 years earlier. Eiffel used the same technology, compressed air to keep the water out of the caissons, which the Roeblings had used. The four concrete pads are connected to each other by four concrete walls (below ground), making one solid foundation. Because the columns have a radical slope inwards at ground level, the pads had to be angled to match, making for a rather odd looking form.

All the iron pieces used in the tower were fabricated in Eiffel’s shop located on the outskirts of Paris. These pieces were precision made to a tolerance of 1/10 of a millimeter. These iron pieces were assembled in the shop so that subsections of the tower that were roughly 5 meters in length were shipped to site for finally assembly. On site were between 150 and 300 skilled workers (depending on the project phase). The pieces were bolted together in the factory and the bolts were replaced by rivets on site. Rivets were heated until they were red hot then they were hammered until a heads were formed. The rivets provide a tighter bond than nuts and bolts because they contract as they cool, but the rivets require much more effort than bolts as they have to be hammered with a sledge hammer and this hammering is done vertically. As anyone who has ever wielded a sledge hammer knows, swinging the tool vertically is a physically demanding activity. Now add to that demand the requirement to hit a target as small as a rivet and keep that up all day!

The tower was constructed in 3 phases or levels, the first level including the base, the second level, and the top. The construction plan called for twelve 30 meter temporary scaffoldings and four 40 meter scaffoldings to be used for construction to the first level. Steam cranes were used to lift the pieces and hydraulic jacks were used to place them. The cranes traveled on the runners which would later be used for the tower’s elevators. The plan was so accurate that despite the enormous quantity of pieces to assemble, the first stage of the tower was completed by December 7, 1887.

The elevators which would ferry tourists to the 3 levels built into the tower had to travel along the 4 columns as there was no central structure to support elevators. The problems of elevator travel to the 3^rd level at the top of the tower (the better part of 1,000 feet) and travel in the arc shape of the columns had to be overcome.

Eiffel overcame these problems by dividing the tasks vertically (separate elevators to the first, second, and third levels), and horizontally between the four columns: North, South, East, and West. Eiffel engaged the French company of Roux Combaluzier Lepape to construct the elevator apparatus in the East and West columns, to the first level. They provided an apparatus using hydraulic power, chains, and guides on the sides of the elevator cars which rolled on tracks set into the columns.

Otis Elevator was engaged to provide elevators to the 2^nd level in the North and South columns. Otis provided a double decker cabin, using cables and hydraulic power to maneuver the cabins up and down the columns. Otis also installed their safety system that would lock the cabins in place in the event of a cable failure. The problem of carrying tourists to the third level was solved with two counterbalancing cabins capable of holding 110 passengers each or 8 tons, and a massive (81 meters) vertical piston to provide lift. This solution required passengers to change cabins midway through the journey and their experience was made more exciting by the narrow walkway (safety railed) which they used to make the switch.

The final phase of the project was the painting of the tower; painting of the iron tower was essential to protecting it from rust. Painting the tower didn’t present the project with any technical problems other than the huge areas that had to be painted and the many surfaces and angles that had to be painted.

The entire tower was completed by March 31 1889, five weeks ahead of the May 6 deadline.

What We Can Learn from Eiffel

Planning  Eiffel engaged a team of fifty engineers and designers who produced 5,300 drawings for the tower. It is said that if bridge construction were planned the same way as software projects there wouldn’t be a bridge left standing. One of the reasons that people like Eiffel were successful is the focus on planning. The team still has to execute the plan but without a good plan there is no hope of success.

Risk Management  Eiffel took a huge risk implementing elevators to convey visitors to the 2^nd and 3^rd floors of the tower. Elevators were in use by this time, but had never before been used at these heights or to carry the loads expected. Eiffel mitigated the risks so effectively that the last original elevator wasn’t de-commissioned until 1983. One of the strategies he used to mitigate this risk was engaging the Otis Elevator Company to provide elevators for the project. Otis invented the safety elevator which locks the elevator car in place in case of any mechanical failure.

Eiffel was also innovative in addressing the risks of physical injury and death during construction of the tower. Up to this point tall buildings were entirely enclosed and falls could be restricted to one floor. No one had ever built anything this tall in an open concept before and the risks of a fall from a great height were dramatically increased by this fact. Eiffel mitigated this risk by the use of movable stagings, guard-rails and safety screens. These measures were effective in limiting the accidents on the project and it only experienced one fatality.

Change Management  The tower was originally designed with bulb shaped structure at the very top, massive concrete pedestals to support the columns, glass walled rooms and halls at the first level, and various other features including huge arches which joined the 4 columns and supported the first level. All these features were removed from the plan with the exception of the pedestals and the arches. This not only allowed the project to complete on budget, decisions on these changes were made before time and money were invested in their construction.

Quality Management  The tower was designed to offer the minimum wind resistance possible. The design is so successful that the very top of the tower will only move 2 – 3 inches in high winds. By comparison, the effect of the sun on the tower is far greater – the tower top will deflect up to 7 inches due to the sun’s heating of the iron on one side of the tower.

Time Management  Eiffel had a very tight timeline to work with, 2 years and 4 months. Given the technical challenges that had to be overcome and the scope of the project, this was a very demanding goal. Eiffel and his team managed to bring the project in 5 weeks ahead of schedule. That success was due to several factors: the high degree of detail that went into the plan, the speed at which technical challenges were overcome, the commitment of the team working on the project, and innovations that Eiffel introduced to keep to deadline. Eiffel succeeded in beating the deadline without sacrificing any of his strategies for worker safety.

Facts and Figures

Tower Height: The tower was originally built to a height of 300 meters (984 feet). This was later increased to 324 meters (1063 feet) with the addition of communications antennas.

Tower Weight: 10,100 tons. Weight of the metal structure: 7,300 tons. The weight on the pads at the four corners of the tower is only 4.5 kg per square centimeter. Another piece of trivia that I find fascinating: the weight of the tower is no greater than the weight of the air in a cylinder large enough to enclose the tower. The total weight of the tower includes the 60 tons of paint required to protect it from oxidization.

Composition: The tower consists of 18,038 individual parts fastened with 2,500,000 rivets.

Records: The Eiffel tower was the tallest structure in the world until the Chrysler building was completed in 1930.

Number of Visitors: The Eiffel Tower welcomed 6,719,200 visitors in 2006 over 200,000,000 since it opened in 1889.

Construction Time: 2 years, 2 months and 5 days

Gustave Eiffel left an enduring legacy which the country of France and the whole world have enjoyed since its opening in 1889. It is a rather unique construction undertaking because it has no practical purpose such as the Hoover Dam or Brooklyn Bridge; its sole purpose is the entertainment of tourists. Yet, as the 200,000,000 tourists who have visited it since its opening can attest, it is a great commercial success.

His careful attention to detailed planning, as illustrated by the 5,300 engineering drawings used in its construction, enabled Eiffel to complete the project in just a little over 2 years. He not only had to erect an iron building close to 1,000 feet in height, something no-one had ever attempted before, he had to solve the technical problems of transporting tourists up to the 3 levels of shops and restaurants built to entertain them. He managed all this and still brought the project ahead of schedule, with 5 weeks to spare.

Eiffel was also successful in creating a safe work environment for the crews working on the tower; only 1 workman died during its construction. We should keep in mind the relatively small number of workers involved before making comparisons to other projects such as the Brooklyn Bridge or Hoover Dam though. Eiffel’s project only involved 300 workers and not all of them worked at height.

The one area that Eiffel could have improved was his communications with the project’s stakeholders. I’m not referring to his customers, the commissioners of the Paris Exhibition, I’m referring to the artists, authors, sculptors, and architects who complained of the project to the press and commissioners. He made no attempt to engage them before the project began and had to deal with their negative action when they became aware of the plans. Communicating with these people before hand and involving them in discussions about the aesthetics of the structure could have averted this conflict. I wouldn’t be too critical of Eiffel however. The concept of engaging the community in which large construction projects are to take place is a relatively new concept in the project management world and certainly not prevalent when Gustave Eiffel built his tower.

Gustave Eiffel has had the last word in the debate over the technical viability and beauty of the Eiffel Tower. There are over 200,000,000 people who have visited and admired the tower and many, many more who have viewed it in movies, pictures, and postcards. The Eiffel Tower is probably the single most recognizable landmark in France today. It captivates its audience with its beauty and awes them with its size.