What makes the eiffel tower stable

Alexandre Gustave Eiffel was born in Dijon, France. In , Eiffel established his own company — Eiffel et Cie from , later Compagnie des Etablissements Eiffel from — with which he designed and built railways, bridges and structures in Europe, Africa, South America and Asia. Eiffel built with his team more than a hundred significant bridges and other structures, gaining a lot of practical experience and establishing his reputation as someone with the greatest structural skills of all his contemporary engineers.

Parts of his work are two remarkable bridges that are considered as the general rehearsal for his highest achievement, the Eiffel Tower:. In , an open competition was announced for the centerpiece of the Exposition Universal in Paris, and all entries had to include a study for a meter foot metal tower on Champs de Mars.

Eiffel was assisted in the project by his leading engineers, Maurice Koechlin and Emile Nouguier, and the architect Stephen Sauvestre. The tower structure is built with 7, tons of wrought iron. Horse-drawn carts transported preassembled parts of the structure from the company workshop near Paris to the site. Up to workers on the site and in the workshop were involved with fabrication and erection. The construction started on January 28, and was completed after two years, two months, and three days on March 31, The height of the tower when completed in was In the puddling process, impurities are burnt out of pig iron through the aid of iron oxides and a current of air through the furnace.

The purified iron was collected in balls before being squeezed and hammered out. Also forming the original framework of the Statue of Liberty, this type of wrought iron is readily able to accept protective coatings and capable of withstanding corrosion and fatigue.

The behavior of puddled iron was just one of the many factors that the experts at CETIM needed to consider when creat-ing their model of the Eiffel Tower. The total framework of the tower itself weighs about 8, tons. Like many modern structures, the Eiffel Tower uses an arrangement of criss-crossing 'X-shaped' beams known as a truss.

This is a very efficient way to engineer structures by relying on the inherent strength and stability of triangles. If you zoom into one of the Eiffel Tower's trusses, you'll find that they aren't as solid as they seem - each of them are made up out of smaller, similar trusses. The material has more holes than it has iron. This hollow form contributes to the tower's mind-boggling lightness. The next time you go over a bridge, look carefully, and you're likely to see the same idea at play.

Once you've figured out how to build a lightweight tower, how do you ensure that it stays standing? The Eiffel Tower has to contend not just with gravity but with the considerable toppling force of the wind. To counter this, its sloping curve closely follows the most efficient shape for resisting the wind. The trick to building a well engineered structure lies in transferring the forces from where you don't want them to act to where you want them to act.

Eiffel understood this. The shape of his tower has the special property that the combined force of the wind and the tower's own weight will flow down the legs of the tower, all the way down to the strong foundations. In physics terms, the tower has just the right shape so that the torque, or toppling tendency, generated by the wind is balanced by the torque due to its own weight. In the interview where he responds to his art critics, Eiffel describes this idea. It was wind resistance.

Well then! I hold that the curvature of the monument's four outer edges, which is as mathematical calculation dictated it should be [ By understanding how forces flow, Eiffel's engineers could design an optimal structure, putting stuff only where it's needed, and leaving it out where it isn't.

The method that they used to visualize the flow of forces has a curious connection with the science of bones.

The engineer, who had been busy designing a new and powerful crane, saw in a moment that the arrangement of the bony trabeculae [spongy bone] was nothing more nor less than a diagram of the lines of stress, or directions of tension and compression, in the loaded structure: in short, that Nature was strengthening the bone in precisely the manner and direction in which strength was required; and he is said to have cried out, "That's my crane!

When an engineer looks at a structure, she looks beyond the material and sees the forces that act on it - it's a bit like owning a pair of X-ray goggles. These forces come in two types - pushing forces that squeeze an object inwards, and pulling forces that stretch an object outwards. Every physical object that you encounter, from a table or a chair, to a bridge or a skyscraper, is basically a big party of these pulling and pushing forces or as engineers refer to them, tension and compression forces.

So when Culmann was designing his crane, he was using his newly devised method of 'graphic statics' to map out these push and pull forces. And this is what he drew. On the left is a drawing of the push and pull forces in the crane he was studying. And on the right is a similar drawing of push and pull forces in the top of the thigh bone the femur. These images, adapted from Culmann and Wolff's publication in , represent the first collaboration between an engineer and an anatomist.

The Eiffel Tower is unquestionably modern in its shape, which is distinct from the Neo-Gothic, Neo-Renaissance and Neo-Baroque styles that were popular in the 18th and 19th centuries, according to Gudek Snajdar. But its material truly made it stand out. The Eiffel Tower is also a more democratic, and therefore modern, structure than other monuments of the time, according to Gudek Snajdar. Gustave Eiffel insisted that elevators be included in the tower, but they had to be imported from an American company because no French company could meet the quality standards, Gudek Snajdar said.

That was something that was before only accessible to a few wealthy people that could afford flying in a hot air balloon. But now, it was rather cheap and anyone could enjoy the view on a city from it," she explained.

It's democratic and not only available to a few of a wealthy people. But people of a different social background could use it and enjoy it. The tower was intended as a temporary structure that was to be removed after 20 years. But as time passed, people no longer wanted to see the tower go. By the time the Exhibition was over, most Parisians were proud of the structure," said Iva Polansky, a Calgary-based novelist and historian at Victorian Paris.

Gustave Eiffel was also not keen on seeing his favorite project dismantled, and so he set about making the tower an indispensable tool for the scientific community. Just days after its opening, Eiffel installed a meteorology laboratory on the third floor of the tower. He invited scientists to use the lab for their studies on everything from gravity to electricity.