At the end of the 19th Century ,in the light of recovering French economy after the Franco-Prussian War, French republic announced the opening of a competition to design a 1000-foot tall tower for the 1889 Universal Exposition. The location of the tower was determined to be at Champ de Mars in Paris. Gustave Eiffel’s company engineer, Maurice and Emile alongside the architect Stephen Souvestre came out with a proposal to enter the competition. Their blueprint was selected unanimously out of all the proposal from all over the world. However many challenges were faced by Eiffel even before the construction began. From lack of financial fund to the unbelieving heart of the public to ascension of a tower doubling the then tallest structure in the world, Washington monument, Eiffel tower was built on the courage to overcome the people’s concept of ‘’height limitation’’ and Eiffel’s confidence and knowledge in structural construction.
One of the main reason of Eiffel tower being made of wrought iron because of the experience of Maurice and Emile in iron railroad bridges and Eiffel’s experience in his previous project including the iron framework of Statue of Liberty. This gave them a head start in this purely iron-made tower.
According to the study commissioned by the Eiffel Tower Operating Co. , the chosen material is among the many factors that kept Eiffel standing until now. The elastic and ductile puddled iron has high strength to weight ratio and is able to withstand fatigue. With the fact that the weight of the air surrounding exceeds the weight of the tower itself, it can been seen that iron is a light yet durable material.
However, due to the characteristic of metal, Eiffel tower expands and contract as temperature changes. Based on the CETIM’s model analysis, temperature changes and extreme wind conditions may cause the tower to double its weight and sway but it is not enough to cause any threatening destruction.
The most concerned design criteria faced by Eiffel’s would be the stability of the tower. Despite the criticism from the public, he was certain that his design and the way of the tower’s construction was going to work out.
After winning the bid for the Universal Exposition of building a 1000-foot tower, Eiffel and his engineers worked hard in improving the design. 1700 drawings were produced on the supporting framework of the tower and 3629 drawings detailed renderings were produced as the blueprint of the latticework tower. Although the deadline for the construction was tight but the time spent for the calculations for every pieces of the iron truss were done manually ,one at a time, was prioritized. The production of blueprint was not an easy job as the standard of precision was set very high where rivet holes’ position was specified to 0.1mm and the angle to 1 second of arc.
To increase wind resistance, the four curved piers of the tower supported by sand jacks were purposely made to tilt at an angle of 54 ° inwards. This design had enable the thrust of the whole tower to be exerted perpendicularly to the foundation.
The legs of the tower were designed to bear the weight of 3 platforms, where the first platform was designed to be at 186 feet ,following by the second platform at 377 feet and the third platform at 890 feet from the ground.
Before the construction began, a series of borings were carried out in preparation for the laying of the foundation. The result of the boring showed that the ground of Champ de Mars was composed of a layer of sand and gravel of different depth on top of a deep stratum of clay with capability of supporting weight in the range of 45 to 55 pounds.
In the first month of 1887, foundation works finally took place on the ground of Champ de Mars. The base where the four piers of the tower would sit on was deeply excavated. A bed of quick setting cement 20 feet deep was poured into...