Wellington Arch

Structure Information

The Wellington Arch is located at the corner of Hyde Park, but it was first located at Hyde Park Screen. Hyde Park Corner is thought of as the entrance to London. The arch was designed by Decimus Burton, an architect of the “eclectic style of the age,” and it commissioned by the Office of Woods and Forests. The Wellington Arch was built between 1825-1827, and it was constructed in honor of Arthur Wellesley, the 1st Duke of Wellington. A statue of the Duke was placed on top of the arch in 1846, and the quadriga (a chariot drawn by four horses) sculpture was erected in 1912. The Wellington Arch was built after the defeat of Napoleon at the Battle of Waterloo in 1815, and it is a distinct London monument. The Wellington Arch and the Marble Arch were both created during a period of “contemporary grand neoclassical building projects” The governing classes of Britain wanted London to reflect the country’s wealth and international status. [1]

Figure 1: Wellington Arch [1] 

Historical Significance

Decimus Burton was tasked with designing new railings and gateways for the royal parks in London, and his initial designs were fairly modest. Since Green Park was seen as the outer entrance to Buckingham Palace, Burton produced a more elaborate second design. Buckingham Palace was being remodeled by John Nash for King George IV, and the arch was designed in a more ornamental style to suit the monarchy. The estimate for the arch was approved in 1826, but the quadriga sculpture was not paid by the Treasury in part because the Buckingham Palace renovations were so expensive. The Wellington Arch was completed but left without the decorations from Burton’s second design. The Wellington Arch does not have any innovative structural engineering designs since arches have been around for thousands of years. It was built around the same time as the Marble Arch and the Euston Arch in the 1830’s. Great Britain was an emerging world power and the feeling of pride and confidence was reflected in the art and architecture. [1]

Cultural Significance

Committees were formed in the 1830’s to created national memorials to two heroes of the time: Lord Nelson and Duke Wellington. The Wellington Memorial Committee chose the equestrian statue of Wellington and approved Matthew Cotes Wyatt as the sculptor. This decision caused a lot of controversy at the time between the committee, the public, the press and Parliament. The equestrian state designed by Wyatt was called “both ugly and completely disproportionate to the arch.” There were demands to take down the statue, but Wellington strongly favored the statue and stated that he would resign from all public posts if the statue was taken down. Duke Wellington was the commander-in-chief at the time, so the Queen and government stopped their demands for the removal of the statue. The statue of Wellington and the controversy surrounding it has been called “the greatest sculptural fiasco of the 19th century.” It caused an artistic debate and is an example of the British attitude to public art. The Wellington statue was removed in 1883, and in 1912 the quadriga statue was placed on top of the arch. The quadriga state was designed by Adrian Jones and is “a masterpiece of British public sculpture from its Golden Age in the late 19th and early 20th centuries. Today, Wellington Arch is placed on an island in the middle of the Hyde Park Corner roundabout. It was rebuilt in the current location 1883-1885 reusing the original materials. The facing masonry is of Portland Stone, and beneath the facing masonry is London stock brick. The interior of the arch has five stories, with rooms and a flight of cantilevered stone stairs on both sides. Viewing columns on the columns on the east and west sides were created 1999-2000 by the English Heritage and refurbishment during 2011-12 created a temporary exhibition on the third floor. [1]

Structural Art

The Wellington Arch does satisfy the following requirements for structural art: scientific, social, and symbolic. The time period that the Wellington Arch emphasized the construction of elaborate triumphant arches, during a time when Great Britain emerging as a great world power. The symbolic natural of the arch is shown in the depiction of Duke Wellington, who was famous for defeating Napoleon at the Battle of Waterloo. The scientific aspect of structural art, however, is not satisfied since there is no new or innovative technique used for the construction. Since it does not satisfy all three aspects, it would be difficult to call the Wellington Arch a piece of structural art.

Structural Analysis

The construction materials used for the Wellington Arch was London stock brick, faced with Portland Stone. The beams are made from cast-iron for strengthening. It has Corinthian beams and pilasters. [2]

The structural system is an arch, and it carries loads through compression. The keystone is inserted into the center of the top of the arch and pushes the stones into compression. The load path of the arch is down and through the abutments.

Figure 2: Load Path of Wellington Arch [1]

The following are the material properties of Portland stone: compressive strength of 38-39.04 MPa, density of 2330 kg/m^3, and a flexural strength of 3.5-7.55 MPa. It is assumed that the width of the arch to be 6 meters, and the max height of the arch to be 18 meters. The diameters of the columns is assumed to be 0.8 meters. The modulus of elasticity of stone is assumed to be 50 GPa.

The thickness of the Portland stone above the arch is assumed to be 1.5 meters. To calculate the uniform load acting on the arch, the following formula is used:

The width of the Portland stone acting on the arch is assumed to be 3 meters. To calculate the uniform load acting on the arch, the following formula is used:

Figure 3: Reaction forces of arch [2]

To calculate the reactions at the supports, take the sum of the moments in the y-direction:

From the cables the following reaction force is calculated:

RAH = (w*L^2)/(8h)

=((102,858 N/m) *( 4m)^2) / (8*12 m)

RAH = 17,143 N

The max force in the cables is calculated as follows:

Fmax= ((RAH)^2+( RVH)^2))= (17,143)^2+(205,716)^2

Fmax= 206, 429 N

The max force at the abutments is equal to the force on the buttresses. The buttresses will need to be designed for overturning using the following analysis. The height of the buttress is assumed to be 2 meters.

The angle is determined as tan^-1(205, 716/17,143)= 85.2 degrees. The width of the buttress (d) is assumed to be 0.25 m. The length of the buttress into the page is assumed to be 3m, the same as the length of the thickness of the arch when calculating the uniform load from density. The flowing equation is used to the moment which would cause the buttress to overturn.

Figure 4: Force on buttresses

The moment that overturns the buttress is calculated to be 12,593.5 N*m.

 

Personal Response

I thought the Wellington Arch stood out on the roundabout so I could see why it was relocated to its present location of Hyde Park Corner. When I first went to Hyde Park, I thought a different arch was the Wellington Arch. I can definitely see that London has a lot of ceremonial arches, some fancier than others. The area around the Arch was very busy, but I unfortunately did not get to see the Life Guards pass through the arch to the Changing of the Guards at Buckingham Palace.

Figure 5: What I thought was the Wellington Arch (still a pretty cool arch)

 

Figure 6: The actual Wellington Arch (on a sunny day no less!)

References

  1. http://www.english-heritage.org.uk/visit/places/wellington-arch/history/significance/
  2. http://www.victorianweb.org/art/architecture/burton/1.html
  3. https://www.telegraph.co.uk/travel/717796/Anne-Campbell-Dixon-explores-the-history-of-Wellington-Arch-which-has-just-been-reopened-after-a-long-overdue-restoration-Making-a-grand-entrance-once-again.html
  4. http://www.stonecontact.com/portland-stone/s4792

 

 

 

 

The Albert Bridge

Structure Information

The Albert Bridge is a road bridge over the River Thames, connecting the Chelsea part of Central London to the Battersea district. The Chelsea Bridge and the Battersea Bridge were opened previously, but the link between the two neighborhoods was not adequate for the growing area so the Albert Bridge was built. The neighborhood of Chelsea expanded in the 1800’s, and Prince Albert proposed the idea of a new and improved bridge to replace the existing ones. The Albert Bridge Company was established in 1863 to build a better bridge, and an 1864 Act of Parliament authorized the construction of the bridge. [1] They were tasked with the operation of the bridge, and toll booths were implemented to generate revenue and cover the cost. [4] The engineer for the Albert Bridge was Rowland Mason Ordish of Messrs Ordish and Le Feuvre, and the construction of the Albert Bridge began in 1871 after initial delays. Ordish was supervised on the project by engineer F.W. Bryant, and the iron and steel work for the project was provided by Britannia Ironworks of Derby. The Albert Bridge was opened to the public in 1873 and given the name in honor of Prince Albert, the husband of Queen Victoria. [1] It was later modified and strengthened by Sir Joseph Bazalgette between 1884—87. The Albert Bridge was once again restored between 1972-1973 and a central pier was added during this time. Last but not least, the Albert Bridge was refurbished in 2010-2011. [1] This is hopefully the last time it will need maintenance, but better safe than sorry!

Figure 1: http://janbutcher.co.uk/?attachment_id=1525

Historical Significance

The historical significance of the Albert Bridge is that it is one of the two central London road bridges to have never been replaced (the other being Tower Bridge). The original design was a suspension bridge but the addition of cable-stays make this a hybrid type of bridge. [1] The six year delay on the start of construction for the Albert Bridge allowed Ordish to design and build the Franz Joseph Bridge in Prague. He used the same principles on the Albert Bridge as the Prague Bridge so the design was not innovative on the Albert Bridge, but he was able to patent this new design after it was utilized on both bridges. [4] In 1857 Ordish patented his system to combat dynamic movements with the catenary cables and the stays each taking a proportion of the loads. [2] The Ordish-Lefeuvre principle, as it was known, was only utilized on those two bridges. When I saw the Albert Bridge, it reminded me of the Brooklyn Bridge with the combination of cable-stayed/suspension bridge design. However, I was not able to find a direct link between the principle patented by Ordish and the Brooklyn Bridge design, which came after. The addition of a central pier in 1973 to strengthen it led to the more traditional beam bridge which still stands today. [4] The weight limit of two tonnes is present, as well as a traffic island at the southern end of the bridge to decrease the size of the vehicles which cross it. [4]

Cultural Significance

The Albert Bridge is an important part of the Chelsea Embankment and the surrounding Battersea Park area around the Thames River. [1] The toll booths were in operation for six years before the structure was bought by the Metropolitan Board of Works, who then made it free to cross the bridge. [3] Proposals to demolish the bridge began in 1926. Both before and after World War II, the Albert Bridge faced the threat of demolition; a 1957 public campaign against demolition saved the bridge. The public campaign was headed by Sir John Betjeman, who described the Albert Bridge as “shining with electric lights, grey and airy against the London sky, it is one of the beauties of the London River.” [1] After the campaign, a weight limit of 2 tonnes was imposed on vehicular traffic on the bridge to combat the fear of bridge failure, and it was almost made an entirely pedestrian bridge. [3] The Albert Bridge was therefore nicknamed “The Trembling Lady” because there was concern that the vibrations from the Chelsea Barracks would cause damage to the bridge. Soldiers from the barracks were advised to break step when marching over the bridge, but those fears and cautions are not present today on the Albert Bridge. [3] When soldiers would march in step, it would cause vibrations of the bridge. This would also occur when large numbers of people cross the bridge simultaneously, with their steps accidentally synchronizing. It’s interesting that this phenomenon happened with the opening of the Millennium Bridge in 2000, with the same problems leading to the vibration and movement of the bridge. [4] I guess we didn’t learn from the mistakes of the past!

Today, the lack of parks or open green spaces on the north side of the Thames River leads to a lot of people walking their dogs across the Albert Bridge to the Battersea Park on the others side. This would not appear to be a huge problem, except that the frequent dog urination on the timber deck causes the deck to rot. [3] However, when I walked across the bridge I did not see (or smell) that this was a problem! The bridge has been used in the background of several movies: Absolute Beginners, Maybe Baby, A Clockwork Orange, Sliding Doors, among others. [3]

Structural Art

Today the Albert Bridge is painted pink, blue and green, a color scheme that is supposed to last around 25 years. There have been numerous color schemes throughout the history of the bridge, but the reason for the most recent one is to increase visibility during fog and dim light. The bridge is supposed to be one of the prettiest bridges in London, so it has the elegance and maximum aesthetic expression part of structural art. However, the bridge started out as a cable stayed bridge but extra supports were necessary to carry the load and suspenders were added. This means the bridge did not use minimum materials so it does not satisfy the efficiency aspect of structural art. By David Billington’s definition of structural art, the Albert Bridge is not structural art.

Structural Analysis

The Albert Bridge was originally intended to be a cable stayed bridge which utilized the Ordish-Lefeuvre principle. The design for the original bridge was a suspension bridge with a “parabolic cable to help take the weight of the central span, aided by 32 inclined stays of wrought iron, inked to one of four octagonal cast iron towers.” [6] The suspension cables were made out of wire steel rope, and they took the weigh of the flat wrought-iron diagonal stays. The diagonal stays provided support for the deck of the bridge. The four towers are made out of cast-iron and stand on the four tapering piers, which are cast-iron cylinders filled with masonry and concrete. The cylindrical iron casting weight 10 tons and had to be transported down the Thames River from the Battersea foundry to the location of the Albert Bridge. The tower pairs on each side of the span are connected by a girder and arch. [6] Sir Joseph Bazalgette, the Chief Engineer of the Board of Works, made modifications on the bridge after seeing that corrosion of iron was already present in 1884. He replaces the steel cables with steel link chains and added a new timber deck. This gave the Albert Bridge more of the traditional suspension bridge appearance, and started the hybrid combination of bridge types. [1] The part which makes the Albert Bridge a suspension bridge is the “deck supported by vertical hangers suspended from catenary chains hung between pairs of towers.” The part which makes it cable-stayed is the “support of the deck from the inclined stays fanning out from the top of the tower, providing greater rigidity.” [1] Strengthening work during 1972-1973 include the addition of “two circular piers connected by a transverse steel beam beneath the middle of the bridge.” In the 2010-2011 modifications, the bridge was refurbished and repainted, and the decking was replaced once again.

Because the aspects of the bridge which make it more of a suspension bridge were added later 10 years after the original bridge opened, it can be assumed that the cable-stayed bridge was sufficient in carrying the load. For the purpose of this analysis, the Albert Bridge will be treated as a purely cable-stayed bridge because the Ordish-Lefeuvre principle is a patented early form of cable-bridge design in a modified form.

The Albert Bridge has a fan design since the cable stays fan out from one point on each of the towers. It a multiple span bridge: it originally had 3 spans before 1973, the addition of a pier in the middle of the main span made the bridge have 4 spans. The 3-span aspect of the bridge means the loads from the main spans are anchored towards the end of the abutments. In a cable-stayed bridge, the cables are in tension while the mast and deck are in compression.

The following are the current dimensions of the Albert Bridge: width of 12.5 meters, total length of 216.7 meters, main span length of 137.2 m, and a tower height of 21 m. To analyze this bridge, the first approximation is to ignore the stiffness of the deck and assume that the cable carries all the load. To simplify the analysis, assume that the cables on each side are lumped into a middle cable. The bridge has a weight limit of 2 tons, so it is assumed that the trucks which cross the bridge will have a max mass of 2 tons. The average length of a truck is 8 meters so approximately 27 trucks can simultaneously fit on one road lane on the bridge. If each truck is exactly 2 tons, then the max live load on the bridge would be 54 tons, or 17, 792 N. The live load along the whole length of the bridge is: (17,792 N)/(216.7 m)= 82.1 N/m. The tributary area for the truck will be half the width of the bridge. The live load on the bridge is calculated to be (82.1 N/m)*(6.25m)= 513.2 N

                                        Figure 2: Simplified live load on bridge

The timber deck is assumed to be English Elm, which has a density of 565 kg/m^3. To simplify the analysis, the deck will be (incorrectly) assumed to be a solid wood beam. With the assumption that the deck is solid wood which has a thickness of 0.5 meter, the dead load on the deck will be:

w = (565 kg/m^3)*(0.5 m) = 282. kg/m^2

The tributary area of the lumped cable is calculated to be:

Figure 3: Calculating tributary area of deck

The tributary area of the deck is calculated to be A=(68.6 m)*(12m)= 823. 2 m^2. Since the tributary area is 823.2 m^2, the load on the lumped cable is calculated:

W = w*A = (282.5 kg/m^2)(823.2 m^2) = (232 kg)

W= (232 kg)*(32.2 m/s^2)= 7470.4 N = 7.47 kN

The total load will then be the live load plus the dead load: 7470.4 N + 513.2 N= 7983.6 N. Since it is assumed that the lumped cable takes the weight of the deck and the live load, the following free-body diagram illustrates the forces acting on the cables:

                   Figure 4: Forces in cable

The angle in the figure above is calculated using the length of ¼ of the main span and the height of the tower. It is assumed that the height of the tower extends from the deck to the fan of the cable-stays.

Considering one cable in equilibrium the following forces are present:

The tension force in the cable is calculated to be 14, 167 N, and the compression force in the deck is calculated to be 11,704 N. A typical cable-stay diameter is 90 mm, so the area is 0.636 m^2. The stress on the cable-stay will be the force divided by the area, or 11,167 N/0.636 m^2= 17,553 Pa.

Personal Response

Going to see the Albert Bridge in person, I had high expectations due to the many praises it has received as the prettiest bridge in London. I thought it was a pretty bridge, but it did not seem like anything amazing. I think this is because the span and height of it seems small in comparison to some other bridges, where the sheer size of the bridge is what makes it so impressive. I think the colors are definitely a nice touch in comparison to other bridges, especially during the time of the day that I visited the bridge and snapped a picture in good light. I think seeing the bridge at night with the lights on would have made it seem even more appealing.

References

  1. https://historicengland.org.uk/listing/the-list/list-entry/1358138
  2. https://www.bristol.ac.uk/civilengineering/bridges/Pages/NotableBridges/Albert.html
  3. https://londonist.com/2016/10/secrets-of-albert-bridge
  4. https://alondoninheritance.com/tag/albert-bridge/
  5. http://www.interserve.com/latest-insight/2010/refurbishment-of-albert-bridge
  6. https://www.britainexpress.com/London/albert-bridge.htm

 

http://janbutcher.co.uk/?attachment_id=1525

 

Spanish Arch in Galway

Structure Information

The Spanish Arch is in fact two arches in the Irish city of Galway, so the name can be a little misleading in my opinion. The Arch is on the left bank of the Corrid River, where the river meets Galway Bay. [1] It was constructed in 1594 by Wylliam Martin, who was the 34th mayor of Galway. The name of the arch was originally Ceann an Bhalla (“the head of the wall”) and it did not become known as the Spanish Arch until much later. It was called “The Head of the Wall” because it marked the start of the city walls, which were designed to protect docked ships from thefts. The city walls also included a bastion, which allowed the soldiers stationed on the walls to fire cannons from them. [4]

 

Figure 1: The Spanish Arch in Galway, Ireland [3]

Historical Significance

The Spanish Arch extends from the wall which was built in the 12th century during Norman times. Arches have been around since ancient times so the structure is not any innovative structural engineering design, nor was a new certain construction technique used. The wall itself does not have as much significance throughout history, but currently the area around Galway Bay is used for eating, drinking, and playing music. [3]

Cultural Significance

Soldiers lived in the town wall and manned cannons on the roof. [1]The fact that the structure is called the Spanish Arch in a small city on the Irish west coast showcases the historical links between Ireland and Spain. The reason for the name is believed to be due to the merchant trade of the region of Galway to Spain, and Spanish ships would often stop at the docks in Galway. In fact, Christopher Columbus is believed to have visited the city in 1477. There is a “Latin Quarter” of the city so the influence of Spanish culture is still apparent. However, there is not a proven link between the Spanish people in Galway and the building of the Arch. [4] Today the Spanish Arch is used as a part of the Galway City Museum, which is located next to the Arch.

Structural Art

I would not call this piece structural art according to David Billington’s requirements for structural art: efficiency, economy, and elegance. There is a well-known sculpture on the top of the Arch called Madonna of the Quays designed by the artist Claire Sheridan. [4] The area around the Arch is a part of the lively Latin Quarter of the city, so the symbolism behind the Arch reminds me of the public’s reaction to the Brooklyn Bridge, but on a much smaller scale.

Structural Analysis

The medieval city walls in Galway were constructed using stone since the stone arches were a method perfected throughout Roman times. The load on the arch would be a distributed load since the only applied load is the self-weight of the stone. If there is a person or a cannon on the city walls (as there was in medieval times), a point load would be applied to the free body diagram. However, for this case the only load is the self-weight.

Figure 2: Load Paths in Spanish Arch [5]

Figure 3: Free Body Diagram of loads on arch

 

Figure 4: Calculating max force in arch

In order to calculate the max forces in the arch, cut the arch at the point where it is the tallest (in the middle of the length in this case). Take the sum of the forces in the y- direction and the sum of the forces in the x-direction to obtain the max force at the pinned ends. The max force occurs at the ends of the arch.

Personal Response

I knew that the concepts behind arches have been understood for thousands of years, but it was actually pretty cool to be able to walk under an arch that has been standing around for close to 500 years. While the arch itself is not that impressive, knowing the load paths behind the arch is interesting and I think it’s fascinating that people were able to understand this in order to successfully build them. Also I was able to witness the area around the Bay being used as a social setting during a nice and sunny day in Galway.

References

  1. https://www.galwaytourism.ie/pThe-Spanish-Arch.html
  2. https://www.historyireland.com/volume-9/ireland-spain/
  3. http://snoozleshostelgalway.ie/spanish-archcladdagh/
  4. http://galwaycity.galway-ireland.ie/spanish-arch.htm
  5. https://pbs.twimg.com/profile_images/935815544053358592/zmC63ql-_400x400.jpg