How was the Eiffel Tower constructed? Part 3

Continuation from an earlier post:  How was the Eiffel Tower constructed? Part 2 
Here is a reminder:

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The Tower sways slightly in the wind. During the storm of 1999, it moved approximately 13 centimeters from its initial position.
But the Tower is also affected by heat. When the temperature is high, that portion of the structure exposed to the sun expands more than the portion in the shade. To “get out of the sun”, the Tower can lean as much as 18 centimeters.

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The different coats of paint:

• During the construction – mainly in puddle iron with very low carbon content – the Eiffel Tower was given its first coat of paint in red iron ocher. Mr. Nourisson then had the second
and third coats applied in linseed oil. Painting was completed in March 1889.
• In May 1889, a glazed fourth coat was applied by the same contractor, Mr. Nourrisson; its reddish-brown color shaded off gradually from the base to the top. Guaranteed for one year, this
one coat alone cost 60,000 gold francs.
• In 1892, the paint job received its first cleaning. The contractor was Mr. Rivière. The previous coat was washed and a new coat of cher-yellow paint applied. The job cost 57,000 gold francs, but with maintenance guaranteed for five years.
• In 1899,it was decided that the Eiffel Tower would be repainted every seven years.
• Since 1988, climbers with video cameras have been monitoring the condition of the paint in those areas most difficult to access.
• December 2001 saw the beginning of the 18th painting of the Eiffel Tower since its construction. For the first time, a new lead-free paint was used, in the interests of protecting the environment. A new timetable was adopted.

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Key figures behind the painting of the Eiffel Tower:

• Weight of paint: approximately 60 tons
• Time required: 15 to 18 months
• Frequency required: the Tower is entirely re-painted every 7 years. The 19th painting is scheduled to begin autumn 2008 and finish at the beginning of the year 2010.
• 25 painters
• Cost of the 18th painting in 2001: 3 million euros

This is the end of How was the Eiffel Tower constructed? Part 3, we will continue later on on Part 4!

As always, for visits while in Paris, please look here.

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How was the Eiffel Tower constructed? Part 2

This is the continuation from an earlier post:  How was the Eiffel Tower constructed? Part 1 Just as a reminder:
– Work on the foundations started on 28 January 1887.
– The foundations were complete by 30 June and the erection of the ironwork began.

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December 7th, 1887: Construction for the legs with scaffolding.

One the legs were constructed as cantilevers* (*Cantilever construction allows for overhanging structures without external bracing.) but about halfway to the first level, construction stopped to later be re-started, in order to construct a substantial timber scaffold as shown on the picture below.

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This  of course, provoked a renewal of the worries about the structural firmness of the project, and exaggerated headlines such as “Eiffel Suicide!” and “Gustave Eiffel has gone mad: he has been confined in an Asylum” showed up in the popular press.

From the time of his project proposal in 1886, Gustave Eiffel knew that the Tower’s service to science alone could protect it from its enemies and extend its life span. At the beginning it was meant to last 20 years and then be destroyed! Eiffel therefore spelled out the uses he had in mind: meteorological and astronomical observation, experimentation in physics, a strategic observation post, a communications base for signaling, a beacon for electric light and wind studies. He said: “It will be an observatory and a laboratory such as science has never had at its disposal. That’s why, from Day 1, all our scientists have encouraged me with such strong fellow feeling.” In fact from 1889 onward, the Eiffel Tower was used as a laboratory for scientific measurements and experiments. Much scientific equipment was installed (barometers, wind gauges, lightning conductors, etc.). Gustave Eiffel even built himself an office on the third floor to carry out astronomy and physiology observations

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Do you know why the Eiffel Tower is made of iron?

What are the advantages of iron? Gustave Eiffel himself gives the answer: “First of all, its resistance. From the viewpoint of loads one or the other of these materials can support, we know that for any given surface area, iron is ten times more resistant than wood and 20 times more resistant than stone.” He points out: “It’s above all in the large constructions that the metal’s resistance makes it superior to other materials. The relative lightness of metal constructions also allows for smaller supports and foundations.” And he concludes: “To give just one example, that of the Exhibition Tower, I astonished more than one person who was worried about the load on the floor of the foundations, by saying that the load wouldn’t be any greater than that of a house in Paris.”

• On hot days, the Eiffel Tower is 15 cm higher, due to metal expansion.

This is the end of How was the Eiffel Tower constructed? Part 2, we will continue later on on Part 3!

As always, for visits while in Paris, please look here.

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