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Dôme des Invalides

Dôme des Invalides

Figure 1: Les Invalides aerial view

Structure Information

Les Invalides, is the complex that houses the Dôme des Invalides. It was proposed by King Louis XIV on November 24th, 1670 as a home and hospital for elderly and sick war veterans. Before the King’s preposition, an establishment that served to accommodate elderly and disabled solders did not exist. The French Parliament funded this project under the King’s command and handed it over to War Minister Louvois, who appointed Libéral Bruant as the architecture of the project. During the completion of Les Invalides in 1676, the complex had fifteen courtyards and was largest court of honor for military parades.

A couple years later construction began on a chapel where the King and the solders could hear the mass in communal.  Due to protocol and decorum issues, the chapel was never completed as planned. As a result, the Minister of War appointed Jules Hardouin-Mansart to take over the architecture of the project. He decided to divide the church into two sections, one section purely solders and the other the royal church. The section of royal church incorporated a marvelous dome, the Dôme des Invalides, which is now the one of the major features of the complex. Jules Hardouin-Mansart completed the chapel in 1679 with the assistance of the notable Libéral Bruant in his last years. The gold-plated dome, which rises above the entire complex was completed in 1706.

By the end of the 17thcentury more than 4000 residents lived in the Les Invalides ruled in the same way as monasteries and barracks, with the solders being divided into companies where they were given tasks. The severely injured and disabled were taken care of in the hospital which was located in the South East section of Les Invalides. This hospital is actually still active today acting as hospital and retirement home for war veterans. This is amazing because the building still serves its original purpose.

Historical Significance

This building was built during the late 1600’s before the construction of Christopher Wren’s noteworthy St. Paul’s Cathedral. Domes during this time faced issues with load transfer from the dome to the walls of the structure supporting the dome. The walls could not support the tremendous load applied by the dome, resulting in the deformation of the entire structure. As a result, Jules Hardouin-Mansart with the assistance of Libéral Bruant incorporated double column buttresses in their design to resolve this issue. This idea was used in the structural design of many future domed structures after Dôme des Invalides. The idea of a three-part dome, as a solution to the tremendous load applied by the dome onto the walls of the structure was not until Christopher Wren’s St. Paul’s Cathedral in the early 1700’s.

The building that Dôme des Invalides rests on is elegant and symmetrical. The curve of the dome is offset by a straight angle of the building its supported by. As a result, the dome appears sits on the building like a crown. Besides the lantern on top the dome, the façade of Dôme des Invalides appears to be entirely symmetrical, evenly distributing the load path of the dome onto the buttresses.

Cultural Significance

Because Les Invalides was largest court of honor for military parades during its time, it was also a target during the French Revolution. On July 14th, 1789 Les Invalides was invaded by Parisian rioters who seized cannons and muskets stored in its cellars. The same cannons and muskets were used against the Bastille, which was a fortress in Paris known for its important role in internal affairs and a state prison, later the same day.

The First Consul of Paris ordered the installation Turenne’s tomb, under the Dôme in 1800 and dedicated a funeral monument to Vauban in 1808 opposite from Turenne’s tomb. Henri de La Tour d’Auvergne Viscount of Turenne better known as Turenne was a French Marshal General and one of the greatest generals in history. Sébastien Le Prestre de Vauban was French military engineer who served the King and was commissioned as a Marshal of France. During his time, he was a leading engineer because of his skills and innovation.

In 1846, the crypt of Les Invalides, which is located directly under the Dômewas prepared to receive Napoleon I’s tomb. On May 5th, 1821 Napoleon I died on the island of St. Helena, where he was exiled since 1815. He was buried near a spring on the island until 1840, when King Louis-Philippe decided to transfer his body. Napoleon was entombed with an honorable ceremony during his transfer. Napoleon Bonaparte was a French statesman and military leader who become notably prominent during the French Revolution. He dominated European and global affairs while leading France against a series of confederacies in the Napoleonic War.

The vault of the church is decorated with flags and trophies that were taken from French enemies. These flags and trophies were originally hung from the vault at the Norte Dame Cathedral until the French revolution. After the French revolution, the items that survived were transferred to Les Invalides in 1793. Today showcasing of these flags and trophies are positioned on the cornice of the church, showing the military history of France from 1805 up until the 20thcentury.

Today Les Invalides is a historic museum that exhibits the tombs of the many important people to France. It also serves as a hospital for injured and disabled war veterans. This is remarking because it still serves its original purpose from so many year ago. In 1989 the dome went under construction. Major renovations were done with the efforts of embellishment. These renovations ended up using 12kg of gold and restoring paint on the underside of the dome. Although the costs of these renovations seemed a lot, the people of France did not mind. They adore this building for its rich history, and culture, along with the beauty and elegance its brings the to the skyline of Paris.

Figure 2: Napoleon I’s tomb

Structural Art

The evaluation of structural art depends on the equal use of the three E’s according to Billington: efficiency, economy, and elegance. The goal of efficiency and economy is to design a structure that uses the least amount of material, and money. The efficiency of the structure has to carry on even after the construction of structure is completed. This means that any repairs the structure may need as a result of initial design goes against efficiency in the terms how long the structure successfully performed its function without the adding of new material. It would also go against economy in terms of the money spent in structural repairs. As for elegance, the structure must be aesthetically pleasing, while defining its engineered structures and creativity.

The Dôme des Invalides seems to be efficient in the aspect of longevity. It has not needed a lot of repairs other than for embellishment. The materials used to create the structure were efficient for its time period. Although now structures made from masonry, where reinforced concrete can be used are not considered to be efficient. Likewise, the Dôme des Invalides seems to be economic because money did not have to be put into construction of structural repairs, and overall the building is socially accepted, attracting many Paris tourists. The Dôme des Invalides is extravagantly beautiful and aesthetically pleasing. The Dôme is wrapped in gold leaf and towers over much of Paris’s skyline. It also showcases its engineering creativity with its symmetry. Therefore, according to Billington the Dôme des Invalides exemplifies structural art.

Figure 3: Exterior view of Les Invalides

 

Structural Analysis

Basic design principles and assumptions of arch analysis were applicable to the analysis of masonry domes during this time period. Different methods, like equilibrium and elastic methods, were developed to analysis masonry domes. Equilibrium methods rely on the domes geometry and self-weight to determine its stability, while elastic methods use material strength to determine force. Both methods determine the primary internal forces of the dome, meridional force and hoop force. The Dôme des Invalides is made of brick, and the exterior is wrapped in gold leaf. Domes during this time faced issues with the transfer of the tremendous weight from the dome onto the walls of the structure. As a result, such as double-columned buttress was employed in order to be able to support the entire load of the dome. The golden dome itself is topped with a lantern that measures 107 meters in height making it one of the tallest structures in Paris.

Load Path

The lantern of the structure transfers its self-weight down to the gallery which then transfers its load to the hemisphere of the dome. The dome distributes this load into the walls of the structure which are supported by buttresses. These double-columned buttress take the entire load of the dome and transfer is down into the ground of the structure.

Analysis

Diameter of dome: 114 ft (assumption) => Radius of dome: 57 ft (assumption)

Density of Brick: 115 lb/ft3(researched)

Thickness of dome: 18 inches or 1.5ft (researched)

Surface area of the dome: 20414.07 ft2

I assumed the measurement of the diameter of the dome based on the ratio of the entire height of the building, which was given from my research, to the measured length of the diameter on google maps. I used to google maps to establish this ratio by measuring the height and comparing it to the diameter forming a ratio. I assumed the dome to be a perfect hemisphere. I based this assumption on my research which stated the to be dome be symmetrical. Also just by looking at it, it looked symmetrical. As a result the radius of the dome is half the diameter throughout the dome, making the height of the dome equal to the radius.

Both the Meridional Forces and the Hoop force are in compression because meridional forces are like arches and are always in compression and we can assume the angle for the hoop force is less than 51.8 degrees, so it is also in compression.

As far presentation to stakeholders for the construction of this structure, there were none. The construction of this structure was a command from the King. As far the design, it did not have to be negotiated either because the architect was appointed so whatever he design was relatively what was going to be built. The only thing that may be changed was the appointment for a new architect, during the construction of the church which supports the Dome. This was a result of the original architects old age.

Personal Response

I spotted this structure from the second level of the Eiffel Tower during the Tour. It was so beautiful amongst the skyline of Paris. I asked around to see if anyone know what the structure was, but nobody seemed to know. Not too long after the tour guide started talking about the structure. I immediately listened in to find out it was the Dôme des Invalides. I was astonished with its history and the fact that it still fulfills its original purpose. Honestly if I had just read about this structure, I probably wouldn’t have been as interested. The gold glistening in the skyline is what really caught my attention.

References

http://www.eutouring.com/history_of_les_invalides_paris.html

https://www.britannica.com/place/Hotel-des-Invalides

http://www.musee-armee.fr/en/collections/museum-spaces/dome-des-invalides-tomb-of-napoleon-i.html

 

Comments

  1. jgarrett39 says

    This is a very cool structure! I did not know this building contained so much history. I loved reading about all the different events that have happened here. I wish I had known about this place when we were in Paris because I definitely would have gone to see it. I also liked your analysis on the dome and the forces occurring on it. Those huge numbers really show why the original designers had trouble with deformation!