To make the project more acceptable to public opinion , Nugier and Kohlin instructed the architect Stephen Sovestra to work on the appearance of the project .
Co-investor proposed stone pedestals to ennoble the lower part , monumental arches to connect the columns and the first level , large glass halls on each level , bulbous design for the top and a variety of other decorative features allowing to decorate the entire structure . As a result , the project was simplified , but some elements , such as large arches at the base , were preserved , which in part gives it a very distinctive look .
The curvature of the rack is mathematically determined to offer the most effective resistance to wind . As Eifel himself explains : " All the cutting force of the wind passes inside the front edge rack . The lines directed tangentially to each vertical with the point of each tangent at one height will always intersect at the second point , which is exactly the point through which the stream flows , resulting from the effect of the wind on that part of the tower support located above the two indicated points . "
The assembly of the support began on July 1 , 1887 , and was completed twenty-two months later .
All elements were prepared at the Eifel factory , located in Levallois-Perret , on the outskirts of Paris . Each of the 18,000 elements used to build the Tower was specially designed and calculated , traced to the nearest tenth of a millimeter , - and 0then 3 assembled - together , forming new pieces of five meters each . The team of designers , who worked on large projects of metal viaducts , was responsible for 150-300 workers at the site of the assembly of this giant set of elements .
All metal parts of the tower are held together by rivets , a well-refined construction method at a time when the tower was built . At first , the pieces were assembled at the factory with bolts , which were then replaced one by one with thermally assembled rivets that contracted during cooling , thus ensuring a very tight fit . For each setting of one rivet , a team of four people was needed : one to warm it , the other to hold it in place , the third to form the head and the fourth to hammer it with a sledgehammer . Only a third of the 250,000 rivets used in the construction of the Tower were inserted directly on site .
The bet was to " study the possibility of installing an iron tower on the Champ de Mars with a square base , 125 meters high and 300 meters high ." The project of Gustav Eiffel , businessman Maurice Kohlin and Emil Nugire , engineers and Stephen Souverre , architect , who was selected from 107 applications .
Emil Nugier and Maurice Kehlin , two chief engineers at Eiffel , had an idea for a very high tower in June 1884 . It was to be designed as a large pylon with four columns of lattice beams separated at the base and assembled together at the top and connected to each other by more metal beams at regular intervals .
Support posts on concrete bases are set several meters below the ground level above the layer of compacted gravel . Each edge rests on its own support block , applying pressure to it from 3 to 4 kilograms per square centimeter , and each block is connected to the rest of the walls .
On the side of the Seine , construction workers used waterproof metal caissons and squeezed compressed air so that they could operate below the water level .
The tower was assembled using wooden forests and small steam cranes installed on the tower itself .
The first level was assembled by using twelve temporary wooden forests with a height of 30 meters and four large forests of 40 meters each .