Orange County Branch Newsletter

May 2011

Secretary's Column

Au Revoir Eiffel Tower

It’s spring time again and some of you are probably making travel plans for this summer.  My travel plans were supposed to happen this spring, as an anniversary of sorts, back to Paris to take in the sounds, sites, and ahhh… the baguettes and pastries.  But coordinating my schedule with my husband’s, who runs his own engineering firm, has made it difficult to firm up plans for a week-long trip, let alone 10 or more days. 

My  trip this year was to be a return visit after our very memorable visit 10 years ago.  It was my first time in Paris and I was delighted about my experiences in the “City of Light”.  But what strikes me now is my somewhat reluctance to visit the Eiffel Tower on that trip, as my preconceptions of it being a “tourist” trap had hindered my enthusiasm to visit what has become one of the great civil engineering landmarks of our time.

We took the Metro to the Camp de Mars station and made our way on to the Eiffel Tower.  As we got closer to the tower, I began to see the trusses and other features.  I slowly became awestruck with the details of the steel and the intricacies that make up this extraordinary landmark.  Loud conversations in every language you can imagine, and crowding shoulder to shoulder was part of the Eiffel Tower experience as I enjoyed the fabulous views of the city from the second and top levels. Visibility can be 42 miles out on a clear day from the top, but our best photos were taken from the 2nd floor since our visit happened to be on overcast day. For all my reluctance to visit a “tourist trap”, this is one opportunity I am glad I did not miss.

Completed in 1898 in celebration of the 100th anniversary of the French Revolution, the tower was built for the Paris World’s Fair where the French held a competition for designs for a suitable monument.  Out of over 100 submissions, the open-lattice wrought iron tower was chosen unanimously.  It was the creation of Alexandre-Gustave Eiffel, a renowned French civil engineer who specialized in metal construction such as  the framework for the Statue of Liberty in New York Harbor The design,  a contrast to the older monuments of France and Paris,  was completed in 26 months with just a small labor force. Eiffel made use of the latest knowledge, for that time, of the behavior of the metal arch and metal truss form under loading and  wind forces.  The actual design was by an employee of Eiffel, Morris Koechlin, a junior employee of the Eiffel Construction Business who specialized in  bridges and viaducts all around the world.

Located on the Left Bank of the Seine River at the northwestern extreme of the Parc du Camps de Mars a park in front of the `Ecole Militare (formerly a military parade ground), the Eiffel Tower is situated within the 7th Arrondissement (District) known as Palais-Bourbon.  The current height of the tower is 1069 ft but the structure appears  larger than it really since  there are no other tall structures close to it.  Designed to stand for only 20 years, the Eiffel tower was built of very pure structural iron known as ”puddled iron”, a  light but strong material. This type is a hand-made traditional wrought iron of the late 19th century.  The tower’s base is a square with 328 ft per side. Access to the public is available on three platforms at heights of 189 ft, 380 ft, and 896 ft.  

Its four pillars which provide support for the tower are aligned to the points of a  compass. The base of the tower, with its four semi-circular arches, required elevators to ascend on a curve.  Designed in the US, the elevators are glass-cage machines providing visitors breathtaking views of the city as you ride to the top.. 

On our visit in May 2001, the winds were mild but the tower still swayed  with the wind which can reach speeds of greater than 100 mph at times.  Amassive windstorm in 1999 caused considerable damage to a number of Paris monuments, but the over 100 mph winds  did not hurt the tower at all. Additionally, the tower is designed so that individual parts can be replaced if they wear out.

Although there is always an engineer present at the summit to monitor telecommunications equipment, the tower is usually closed to the public when winds are high.   Under the worst conditions, the sway (deflection) is known to be about six inches. The structure was designed to withstand movements that are easily five times beyond those produced by the highest winds ever recorded in the area, and today movements are monitored by a laser alignment system.  In bright sun light, the tower will lean slightly due to  the  iron on the heated side  expanding slightly.

Although the tower’s design was not initially accepted by all, it has become probably the most recognized structure in the world. Its 2.5 million rivets installed by some 300 steel workers over 2 years included 15,000 iron pieces and 40 tons of paint.  It takes  1652 steps to reach the top. Gustave Eiffel’s  design started a revolution in civil engineering and architectural design. Almost  torn down in several instances , the tower vindicated itself aesthetically over time.  It was saved because of its antenna, which was used for telegraphy and eventually became a part of the International Time Service.  Making use of its stature, French radio and television have used it as a transmission tower,  gaining the structure even more importance.  For 40 yrs it was the tallest structure in the world.

To prove the usefulness of the tower, Gustave Eiffel later began to experiment with enterprises that would make use of the structure.  He had developed a great interest in meteorology, aerodynamics, and radio telegraphy when he had the tower’s peak fitted as an observation station to measure wind speeds and encouraged other types of scientific experiments supporting his new interest. Much of Eiffel’s work eventually helped to expand the science of aerodynamics including wind tunnels.

During its time, the Eiffel Tower has been a part of some interesting antics  including a mountaineer who scaled the tower in 1954, two Englishmen who  parachuted off the tower and a journalist on a bicycle who descended from the first level from either the exterior of one of the legs or down the stairs.   

As with any structure, maintenance is required totaling  50 tons of paint every 7 years to protect it from corrosion.  Each repainting takes about 25 painters about 15 months to complete. Workers are suspended from ropes and chains as they swing above the city while prepping and coating the 113-year-old structure.  With 5 million visitors or so per year, we have to make sure she is in good condition for future generations to experience and enjoy.