Grande Arche de la Défense (Great Arch of Defense)

Structure Information

            Wow, A huge rectangle and a cloud. That was my initial reaction when I first seen the structure.The Grande Arche de la Défense (Great Arch of Defense) not a rectangle is a huge arch located in La Défense, Paris business district. The view from the top of the steps are breath taking. The arch was built to mark the end of the Triumphal Way, the east-west axis that connects the Louvre with La Défense. The purpose of the building today is used for office space. This building was a part of a design competition in 1982, by the president François Mitterrand to commence new construction activity [2]. Architect Johann Otto von Spreckelsen and engineer Erik Reitzel designed the winning entry. They won because their design had stability, simplicity and purity of form [2]. This was cool, because a lot of the designers we talk about in class were involved in design competitions. The designers wanted this to be a place where diverse people could meet and converse. Construction started in 1985, and the building was complete 1989. This project was funded by the government through with a budget of 1.3 billion francs.

 

Figure 1:The Grande Arche de la Défense at Night

Figure 2:The Grande Arche de la Défense Currently

Figure 3:The view under the “Cloud”

Figure 4:The View from the Stairs

 Historical Significance 

            Based on other Paris monuments the arch is twice the size of the Arc de Triomphe and its archway is large enough to fit the Notre-Dame Cathedral. The arch is made of pre-stressed concrete. The cloud spans between the inside of the archway is a tent-like structure. It was created to reduce wind resistance and it also achieves the effect of seemingly reducing the gigantic proportions of the arch [2]. The cloud is made of white plastic panels that are suspended by steel cables to the sides of the arch [2]. Before the designer built the arch the designed three churches. It was stated that he relied heavily on simple geometrical figures, hence the hollow cube (The Grande Arche de la Défense) [3]. The pre-stressed construction tools were also used for the churches, so this material was not new to him. This was his first time building at this scale, so he wanted to make sure it was a cultural icon for the upcoming centuries.

Figure 5:Size of Paris Monuments

 

Cultural Significance 

The 158,000 sq. meters of space is used as a communications center for the La Defense District. It also has digital presentation auditoriums and office space for private parties [3]. The citizens loved the arch, because it was built to mark the end of the Voie de Triomphe (Triumph Way), a large road that connects the east and west of the city. In Paris, they have a thing, where monument mark the end of territories. When I searched for historical events, it was so funny to me that a person getting stuck in a toilet was historical. Margret Thatcher aka Iron Lady aka UK prime minister at the time, got stuck in the toilet. She was visiting the top rooftop, but had to go to the toilet. When she was trying to get out the handle broke, so her body guard had to bust the door open [4]. That was the start of the downfall of the arch.

In 2010-2014, the roof with its viewing platform, gastronomic restaurant, computer museum and conference center, which attracted around 250,000 people a year was closed to the public because of safety concerns. The area around the foot of the north side of the arch has been sealed off after fears of crumbling marble falling on people below, and staff of the French ecology and housing ministries, who occupy the south side, have complained of gloomy corridors and offices with oppressively low ceilings and no natural light [4]. The government gave €200 million to renovate the south side of the arch. Since the government did not give money to fix the north side, out of 30,000 sq. m of offices, 24,000 sq. m are empty and rents have fallen [4]. When I visited, there was renovations going on throughout the entire arch. It

 

Figure 6:The Grande Arche de la Défense during a busy Day

 

Figure 7:The Grande Arche de la Défense Under Construction

Figure 8:The Grande Arche de la Défense Construction Information

 

Structural Art

David Billington stated that structural art can be defined using three E’ principles: efficiency, economy, and elegance. The pre-stressed concrete is used in a wide range of building and civil structures where its improved performance can allow longer spans, reduced structural thicknesses, and material savings compared to simple reinforced concrete [2]. I was efficient to use his material for a structure of this magnitude. Economically the arch is doing okay. It cost 1.3 billion to build the structure, and a big renovation of 200 million. I am sure there are more renovation cost from what I seen. It makes money from tours and rent, so I am sure the cost balances out. It is a simple cubic structure that can be seen easily, so it has much elegance except when it is under construction. Based on those allegations it is structural art.

 

Structural Analysis

            The building is main component is pre-stressed concrete. It is based on a 21-meter grid, where it is mirrored on the top and bottom with four pre-stressed concrete transversal rigid frames of columns attached to main beams of roof and base components [3]. Four additional secondary pre-stressed cross beams in the roof and base are used to stabilize these rigid frames [3]. The roof beams are 70 m long, 9.5 m tall, and weigh 2000 tons each. Four gabled walls were created at 45 degrees, holding 6 horizontal mega-structures on either side. A seven-floor modular was utilized to create a substructure, repeating the modular five times and built simultaneously with the superstructure. For the base, there are twelve foundation piles resting on a limestone shelf 14 meters below ground level. The piles are 8 meters in wide at the base, and the piles flared to 15 meters to meet the structure’s base [3]. The cube’s dimensions are 117 m wide, 112 m deep and 111 m tall [3].

 

Figure 9:The Grande Arche de la Défense Load Path

 

The self- weight of the main beams is given and they are 19.99 m/ton. The self- weight of the secondary beams are considered point load and they are given at 22.04 m/ ton.. The length is 106.90 m, I will calculate the reactions and moments.

Figure 10:The bottom beams analyzed

Figure 11:The Reactions and Moments Calculations

These 3d drawings bellow, shows the structural composition of each component. Allowing the engineer to understand the drawings.

Figure 12:Base Beams

Figure 13:Shear Columns added

Figure 14:Roof Beams Added

Figure 15:Diagonal Shear Walls Added

Figure 16:Bracing Added

Figure 17:Perpendicular Beams Added

Figure 18:Final Overview

 Personal Response

I did not realize how big the cube like structure was. Being able to see the Notre Dame in person and seeing that the it could fit into the arch was amazing. From the pictures, I seen online, I did not know the entrance was steps. The steps blend in so well with the arch.

Figure 19:Me at The Grande Arche de la Défense

References

[1] http://www.aviewoncities.com/paris/archedeladefense.htm

[2] https://www2.deloitte.com/content/dam/Deloitte/cz/Documents/real-estate/Iconic_Buildings_La_Grande_Arche_Smart_16winter.pdf

[3] http://faculty.arch.tamu.edu/media/cms_page_media/4433/grandearche.pdf

[4] https://www.thelocal.fr/20140805/paris-the-not-so-grande-arche

[5] http://famouswonders.com/grande-arche-de-la-defense/

Westminster Bridge

Structure Information

The Westminster bridge is in central London. If that area is hard to visualize, it is the bridge that helps pedestrians get from the London Eye across the river to see Big Ben. When I rode the London Eye, his bridge caught my eye. The original Westminster bridge was designed by Charles Barry to connect the east of Westminster to the west next to the Houses of Parliament in 1750 [1]. There were only two bridges in London at the time, and the London bridge was closed. Over time the bridge was subsiding badly and expensive to maintain, so a new bridge was put into the works [1]. The new bridge, designed by Thomas Page and opened in 1862, consists of seven bold elliptical arches, with three flood arches on the Lambeth ride [2]. The bridge has two footways, two tramways at the sides, and two roadways for traffic. This bridge was funded by an Act from parliament. The Act appointed that £625,000 to be raised by a lottery by the sale of £5 tickets from which £100,000 was to be paid to the commissioners, another lottery that raised £197,500, and £380,500, was granted by Parliament [3]. The total cost of the bridge was £1,103,000.

Figure 1:Westminster Bridge from London Eye

Figure 2:Westminster Bridge

 

Historical Significance 

This bridge was the second bridge in London when it was originally built, so the designer of the present bridge Thomas Page modeled the old bridge which had 13 spans. The new bridge is simple in detail and has seven spans of which are all assumed to be symmetrical. It has a style of Gothic design, which matches with the Houses of Parliament [2]. The downstream parapet coincides on plan with the equivalent parapet of the old bridge, though with a 58 foot roadway and 13 foot footpaths at each side, the present bridge is of almost twice the width [2]. Another difference from the old bridge to the new was the materials that were used, which I will discuss in the structural analysis.

 

Cultural Significance 

Previously stated above, this bridge was built to connect the east of Westminster bridge to the west. There are a lot of tourists, such as myself who visit the London Eye and want to explore more. I used to bridge to get closer to the house of Parliament, where Big Ben is housed. Although, the House of Parliament was under construction, I could view the clock in front of Big Ben a little. From the London eye, this bridge made it easier to go visit may historical places in London with well-known landmarks around it. I thought it was funny how London scheduled the grand opening of the new bridge on Queen Victoria’s 43rd birthday, 24 May 1862 and she did not show [5]. I later learned that she was still grieving from the loss of Prince Albert, who died the previous December [5]. A huge event that happen was the terrorist attack on March 22, 2017. A man drove a grey Hyundai across the south side of Westminster Bridge and Bridge Street, injuring more than 50 people [4]. He then crashed the car into the perimeter fence of the Palace grounds and ran into New Palace Yard, where he fatally stabbed an unarmed police officer and was then shot by an armed police officer and died at the scene [4]. The UK thought the guy had ties with the Islamic military, but found no connections.

 

Structural Art

David Billington stated that structural art can be defined using three E’ principles: efficiency, economy, and elegance. The bridge is very efficient when it comes to holding its weight, and getting the traffic from the east to the west.  In comparison to the old bridge, the new bridge had less spans, which less materials were used. Using less materials would have lowered the bridge cost and made I more economical. The elegance of this structure is simple. The bridge is very thin and does not obstruct views in the river, but enhances it. The bridge reveals its most elegant secret when the sun shines at around 1pm on certain days. The beautiful trefoil cut-outs do a little reverse shadow play: the two lower ‘leaves’ keep their shape, while the top ones stretch out a little into one of the best (unintentional?) Architectural jokes the city has ever known [5]. I thought this was hilarious, because it is no way the designer knew this would happen and be made a joke of. Being able to view the load path and from the three E’s principals, I think this bridge is structural art.

Figure 4:Westminster Bridge Trefoil Cut-outs

Figure 5:Westminster Bridge Trefoil Cut-outs at 1 p.m.

Structural Analysis

The cast iron spans are symmetrical in shape and spring from the piers which face the water.  The spans are 117’ in length and are separated by the 8’ pillars that are built in grey Cornish granite. The caisson method was used to get the base of the bridge.  This helped a portion of the bridge sink o its proper place to create the flat bottomed barged.A horse-powered pile driver and a sinking caisson was used to build the piers.

 

Since the spans are symmetrical, I analyzed one span and assumed that the depth of the bridge was about 71 feet based on the given lengths of the roadway and foot path.  I assumed the height of the load was 8 feet, and the weight of cast iron is 442 lbs/ ft^3.

 

Figure 6:Load path of span

Figure 7:Calculation of weight of cast iron & vertical reaction forces

When I got a number for the load distribution, I calculated the live load at different parts of the main span since the traffic is a live load. I assumed the traffic load as a uniform load. In London, the average weight of a woman is 150 lbs, man: 180 lbs, and child:70 lb. The average of those weights was 133 lbs, in which I assume 400 pedestrians could fit on the footpath giving me a weighted total of 53,200 lbs. The average weight of a passenger car in London is 4,000 lbs and 13 tons for a bus. I assumed 8 passenger cars and 2 busses could fit on the roadway. The total weight for 10 vehicles are 84,000 lbs. The uniform load is 137.200 kips existing on top of the dead load of the cast iron. Using this information, I calculated the vertical reaction forces.

Figure 8:Calculation for vertical reaction forces

Next, I made a cut in the middle of the arch. I was then able to solve for the horizontal reaction force and the maximum force at point A, as seen in.

 

Figure 9:Calculation of the maximum force

 

Personal Response

From research, I did not understand why the original bridge did not hold up and needed so much up keeping. By visiting the bridge, of course I realize that times had changed. Meaning, when the old bridge was built it was built to withhold houses and buggies, no cars, busses and people. Also, I felt a little uneasy being where the terrorist attack took place, because pedestrians on the footpath still are not protected. I think bollards should be put in place for the safety of the pedestrians.

Figure 10:Me on the Westminster Bridge

References

[1] http://www.victorianlondon.org/thames/westminsterbridge.htm

[2] http://www.british-history.ac.uk/survey-london/vol23/pp66-68

[3]https://www.bristol.ac.uk/civilengineering/bridges/Pages/NotableBridges/Westminster.html

[4] http://www.bbc.co.uk/news/uk-39365569

[5] https://londonist.com/2016/08/se

Boston Custom House

Structure Information         

The Historic Structure I chose was the Boston Custom House, which is located downtown Boston.  I had a layover in Boson before coming to London, so I decided to explore Boston. The building was designed by architect Ammi B. Young, and the lot for the building was purchased in 1837 and construction was authorized by President Andrew Jackson. The building was complete in 1847 during James K Polk administration. The Custom House was funded by the federal government, and was the most expensive building built in America, with a price tag of $1.2 million [2] .

 

Boston Custom House Before 1913

Boston Custom House Tower

Historical Significance

The beginning construction process was interesting to me; 3,000 large logs were used was the building’s support [2]. The logs were ugly I am assuming, because they covered the logs with layers of granite, brick and cement to create the sturdy foundation. The twenty-six-floor tower hat was added in 1913 caught my eye at first, because I could see it from the train station [1]. The columns made me think of the ancient Caesar’s Palace, which I learned about in history class. The Custom House has an original design of a Greek temple, with Doric columns on all four sides, and a large domed roof. The style is a Greek Revival-style hence the Caesar similarity.

 

 

Cultural Significance

The Custom House was the center of the communications commission, and the center for Boston’s customs officials. Before Federal income tax were introduced to the United States, the government relied on the duties and taxes collected by the Customs Service at Boston’s wharfs.  The Custom House played an important role in the United Stated in the early 1800’s, they accounted for 1/5 of the money collected for the federal government [2]. The reason I gravitated to this building is because, I asked a restaurant host “what was ha building?” and she replied “the Marriott hotel”. I immediately thought that was a cool looking hotel, and wanted to explore the inside.

The Custom House was completely renovated in the 1990s, and now is a timeshare owned by Marriott Vacations. The concierge in the inside was very knowledgeable about the building, nice, and gave me a fact sheet about the history. When I was leaving, he made the remark “That was easy”, so I am guessing he gives out facts to tourist all the time and is now considered a pro at doing it.

 

Inside Marriott Hotel

Structural Art

Based on the three principles efficiency, economy, and elegance I can determine if the Custom House is structural art. Since, this building played a major role in the federal government finances, I feel that it benefited the economy. It was pricy, but the materials such as granite, brick, cement, and logs made balanced the cost and was efficient. The load for the tower was not transparent, but from the dome down to the columns the load paths can be traced. The Custom House has a Greek elegance about it, and because of its historic look It is structural art. This building screams structural art when looking at the columns. Out of the 36 columns, only half are supporting the structure. The rest are free- standing, so I am guessing the other half are just for looks.

Structural Analysis

After the building was constructed, the exterior of the building consists of 6 columns on each side on a high flight of steps, an order of engaged columns around the walls 20 in number, all on a high basement. The columns are 5 feet 4 inches in diameter and 32 feet high, the shaft being in one place, each weighing about 42 tons. The square footage of the building is 886 sf. The assumption was made that he building is made from stone, so the weight of stone is 133 per cubic feet [3].

Load path

Self Weight Load Path

Self Weight & Force in y-Direction Calculation

Personal Response

By visiting Boston, I now understand why this historical building is well seen verses other historical buildings. I learned that Boston’s pre-1928 building code limited commercial buildings to 125 feet high or approximately 11 stories. Since this was a prominent federal building, the codes did not apply. To somewhat apply to the code, the developers compensated for this restrictive zoning by using innovative massing techniques and by expanding the floor plate [2].  This was my first time in Boston, and I enjoyed exploring and learning about the Historic Structures. When I think of Boston, I think of the Boston Celtics and the New England Patriots. Now I have the knowledge of how federal money was collected before federal income taxes.

Me at Boston Custom House

 

References

[1] http://www.iboston.org/mcp.php?pid=customHouse

[2] http://www.celebrateboston.com/architecture/custom-house.htm

[3]https://www.cityofboston.gov/images_documents/U.S.%20Custom%20House%20Study%20Report%20108_tcm3-43424.pdf