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A little info w.r.t. design of Eiffel Tower 3

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TowerEngineer

Structural
Apr 26, 1999
47
I think the following info may interest some individuals in the world of structural engineering.

As you probably already know: E.T. is 990 feet tall, is constructed of wrought iron, was built in 1887-89, and was designed by the great Gustave Eiffel.

Now for what you probably dont know.

The original design concept for E.T. came from Maurice Koechlin and Emile Nougire, two junior engineers who performed the preliminary calculations.

The tower was almost twice as tall as any other man-made structure that preceeded it. The tallest man-made structures pre-dating E.T. were the Great Pyramids (482 feet), and the Washington Monument (554 feet).

The structure was designed to resist lateral wind pressures of 82 PSF near its top and 69 PSF near its base. To put this in perspective, most American and English engineers were designing for lateral wind pressures of 25 to 30 PSF for most of the tallest building and bridge structures constructed during the same era. Many bridge failures occurred in the 1800s due to a complete lack of consideration of any lateral load whatsoever.

The structure weighs approximately 9547 tons (19,000,000 pounds).
Consists of more than 18,000 pieces and 2.5 million rivets.
It took 100 fabricators and 130 erectors 15 months to build.
E.T. fabrication details consist of more than 5,300 drawings.
45 tons of zinc-rich paint are applied to E.T. as rust inhibitor every 7 years.
There are 1,792 steps to the top of the tower.
Summer temperature increases the height of the structure by about 7 inches.
The ornamental arch below the first platform level serves no structural purpose and was added to the tower after the first platform level had been erected.

It was built in celebration of the 100th anniversary of the French Revolution. Just as in current times, E.T. had its detractors.

Opponents of the tower's construction referred to E.T. as a "tragic lamppost", inverted torch-holder", and the "Grand Suppositaire". When first proposed by Eiffel, E.T. was denounced to as an eyesore; "A dishonour to Paris and a ridiculously dizzy tower like some gigantic and sombre factory chimney".

E.T. was constructed at a cost of 7,799,401.31 French francs -- about 1 million more than Eiffel's estimate.
During the first five months following its completion in 1889, 1.9 million visitors were charged 5 francs for a trip to the top of the tower. Lesser fees were charged for trips to the lower platform levels. Seventy-five percent (75%) of the cost of the tower was recovered in the first year following its completion.
The 1889 visitor number stood as a record until tourism increased in the 1960s. In 1988 (the centenary of its construction) a total of 4.5 million people visited E.T.

The tower was considered temporary and its demolition was initially planned for in the year 1909. Luckily, wiser minds prevailed and the structure is still standing today. It is one of the great engineering and artisitc feats of mankind. This is especially true when one considers that G. Eiffel was a ground breaker in that very little was known of the lateral force applied to trussed towers by action of the wind.

Eiffel's full name is Alexandre Gustave Eiffel. He was educated as a chemical engineer. He was born in Dijon, Fance on 15 December 1832.

Eiffel worked for a railway equipment manufacturer in France after graduating as a chemical engineer in France. Eiffel gave up chemistry for civil engineering at the age of 25 when he was put in charge of the construction of the Garonne River Bridge construction at Bordeaux. His successful completion of the Garonne River bridge (on-time and on-budget), one of the largest structures of its day, helped establish Eiffel as one of the pre-emminent engineers of his time.

One of Eiffel's less well known structures is the Garabit Bridge in France. Eiffel completed its design and construction in 1884. This structure stands second only to Eiffel's great tower as a demonstration of his skill and ingenuity as an engineer. Upon its completion, the viaduct was the highest arched bridge in the world at a height of 400 feet above the Truyere River. The arch spans 541 feet and supports a railway deck 1,850 feet in length. One can almost think of the bridge structure as two 925-foot tall towers laid on their sides.

Iron and steel towers and bridges are similar in design with respect to the application of live loads that are resisted by forces within truss and cable systems that have the benefit of very little structural redundancy.

Gustave Eiffel died at the age of 91 on 27 December 1923.

 
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A little more on Eiffel
I know of at least two structures by Eiffel that are in North America. One is the supporting stucture for the Statue of Liberty in New York Harbor. The other is an all metal church in Santa Rosalia, Baja Sur, Mexico. Any one know of any others works by Eiffel in North America?
 
Mr Eiffel also designed the support structure for the largest ferris wheel of its day, in St Louis at the 1904 world's fair.
 
I wonder if anyone in recent years has put together a computer model of the tower and analyzed it to see what its true response is to wind/seismic and how well the "parts" were designed without the aid of a computer?
 
JAE - A one-third scale re-production of E.T. was recently constructed in Las Vegas, NV. Tthe engineers that designed the replica used a digital computer model to analyze it. Las Vegas is in UBC Seismic zone 4 (highest level of earthquake risk and ground shaking). Their reproduction is similar in form but much is constructed of modern steel rather than wrought iron as was the original.

I have been trying to lay my hands on a copy of Eiffel's book 'The 300 Meter Tower" published in 1900. His book has very complete information with respect to the design of E.T.

It is my understanding that E.T. was designed to withstand 4.0 KN/m^2 wind pressures (no-one considered seismic design forces before the mid-to-early 1900's). Have found alot of A.G.. Eiffel's published drawings on the official E.T. web site.

You or someone else watching this thread wouldn't happen to know where I can get a copy of Eiffel's book (or a re-print), would you?

BTW - Thanks for the copy of 1972 ANSI A58.1
 
Tower....thanks for the interesting thread. No idea on Eiffel's book - try ebay, amazon, etc.....I've heard there are some sites out there that deal in used/old/first edition books. Otherwise, scour the antique stores.

With wrought iron, I'm pretty sure that the ductility in the pieces may be a big question with regards to seismic. Was the LV tower an EXACT replica down to every strut and tie?
 
But does anyone know how many UNIQUE parts the Eiffel Tower consists of??
 
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