Blog 3
Emirates Stadium

Emirates Stadium

Quite possibly my favorite part of visiting Emirates Stadium was being able to read the stories written on the outside walls. Some of them were about inspired players practicing all their lives to play for Arsenal. Some were historical, regaling the tales of its founding members or defining play off games. But my favorite one happened to be one tucked away on the end of a series of stories. It was from a random fan of Arsenal talking about one night in a bar, with the time approaching 1:30. He looked to his left and saw Arsenal’s goalkeeper. He stammered out a hello and began talking to him. Around 3:00 the two are quite drunk and the fan suddenly remembers an important fact and asks the goalkeeper ‘Say, don’t you have a match in 12 hours, when are you calling it a night?’ The goalkeeper responded ‘When the sun starts to come up, kid’. The fan attends the Arsenal match the next and saw the players run out of the tunnel. Sure enough, the goalkeeper also ran out. The fan noticed the goalkeeper looked like he had been awake for a week straight (that’s the polite version of how he looked). Anyways, the match started and Arsenal ended up winning the game in a shutout. The very hungover Arsenal goalkeeper allowed no goals. Being in Europe and not having as cranky of people is great, and one reason is that a story about a goalkeeper staying up all night to drink before a match can be put on a stadium alongside all the other important and famous moments in this football club’s storied history.

Structure Information

Emirates Stadium was first opened on July 22, 2006 [1]. Construction began in July of 2003 [1]. The building is home to the Arsenal Football Club. The architect for this project was Populous (formerly known as HOK Sport) [1]. The structural engineers for this project were from Buro Happold [1]. The funding for the project was all private. Arsenal secured a total of 260 million pounds from loans from various banks [1]. However, one of the banks pulled out as construction started so the stadium’s building was delayed. Middle Eastern airline, Emirates, jumped at the opportunity to help with funding. They lent 100 million pounds in exchange for a 15 year shirt deal with the club and naming rights to the stadium [1].

Figure 1, Emirates Stadium

Historical Significance

The structural design of the roof was very unique. Its four trusses that support the roof is something that is not seen very often. It is presented here because of the type of events taking place at the stadium. The roof only needs to cover the fans in the stands, so there is a rectangular portion taken out of the ceiling about the size of the pitch. The cut out in the roof is not unique, but the four trusses supporting them is.

A special technique used during the construction of the stadium was the attention that was given to the seats. The concrete that makes up the stands was tested repeatedly for dynamic loading that would occur when fans jump/move around during the games [1]. The seating for the stadium was also outfitted with Ferco seats to make the fan experience even more enjoyable [1]. The thought was that if the stadium treated both fans and rivals with respect that they would respect the club in return. You can go to a game yourself to see if that holds true.

Regardless of how that strategy worked out, Emirates Stadium has gained a reputation as the most comfortable seating on the market. Another very cool thing that the stadium has going for it is the lighting for the pitch that the designers employed. They used computer modeling to make sure the lighting and air circulation was adequate for the level of quality they wanted in the grass [1]. The moving air also increased spectator comfort.

The best existing example of this stadium’s design is Estádio da Luz. This stadium is in Lisbon, Portugal and is primarily home to the Portuguese club S.L. Benfica. The stadium also features the same four truss design seen in Emirates Stadium. The view for fans in the stadium is also completely unobstructed. In addition to the unobstructed view, fans are mostly covered by a roof that extends out from the trusses. This roof structure can be a model for future buildings as it accomplishes one important task and one essential task: cover the fans from rain/sun and provide them with a clear view of the pitch.

Figure 2, Estádio da Luz [2]

Cultural Significance

No one died at the stadium during construction, but one worker was badly injured. Michael O’Donovan was kneeling to clean steel shuttering that is used to form reinforced concrete structures when a dump truck ran over his right leg [3]. His pelvis was fractured from the accident and his leg had to be amputated above the knee because the injury was so severe [3]. The City of London Magistrate’s Court determined that the site did not properly separate pedestrians and vehicles [3]. The companies in charge of construction were fined a total of 66,000 pounds in damages [3].

The beginning of the stadium’s tenure as the home of Arsenal was not good. Arsenal is a historically great team and their fans have very high expectations. However, they drastically under-performed in their first seven years. But once the 2013 season finished, Arsenal went on to win three out of the next four FA Cup titles, marking Arsenal as the most successful club in the history of the competition.

The stadium was loved by fans once it was opened. There had been some grumblings about the length of construction but once the stadium was open fans were more than at ease. The new stadium more than doubled the old stadium’s capacity, now allowing 59,867 people to attend games [4]. The land was undeveloped when it was bought and the surrounding area has had a major face lift as a result of the new stadium. The stadium is still used as the home of the Arsenal Football Club.

Figure 3, Arsenal’s Asia Cup Championship in 2015 [5]

Structural Art

To evaluate this stadium on whether it qualifies as structural art we can use the three fundamental principles of structural art: efficiency, economy, and elegance. The main concept behind each of these is to create a structure that utilizes the least amount of material, the least amount of cost both in design and social aspects to the people that will use it, and the most pleasing aesthetics possible.

Looking first at efficiency, this stadium does not seem to utilize the least amount of material from a first glance. The stadium was built to be ‘dramatic venue that highlights their ambition to become a global force in football’ and they used a large amount of materials to do that. Some materials were for the structure, others were used for fan comfort like the roof that extends over the seats. While it is something that was put into place for the fans, it is technically a waste of material. Other stadiums do not have a covering like Emirates. The load path of the building itself is also unclear. Much of the concrete that supports the stadium is covered up by facades making it hard to determine what is happening structurally without building plans. However, the truss structure that composes the roof does have a very light appearance to it. In this aspect, the roof does succeed in a light form with less materials. But, overall as a structure, I would say that this building does not check off on efficiency.

Figure 4, Emirates Stadium’s Dramatic Size

Economy was a problem for this stadium, with construction even being delayed because of it. However, the stadium’s cost can be looked at in a different light when the people funding the stadium are revealed. This stadium, unlike many in America, was entirely privately funded. Arsenal secured loans from various banks and companies to fund the building of this stadium. In terms of the social cost of this stadium for people, there was almost none. They did not have to chip in for this stadium unless they wanted to invest in bonds that Arsenal was selling (one of their other fundraising efforts). The fact that the stadium was privately funded does not entirely qualify it as hitting the economic checkbox though. David Billington, creator and major proponent of the three fundamental principles of structural art, notes that an unlimited budget is a hindrance to economy because designers will add unnecessary things because they have the budget for it. However, Arsenal privately funding this project (and requiring loans because they did not have the money outright for the stadium) means they wanted the stadium as good and cheap as possible. Taking these thoughts into consideration, the stadium does meet the economy criteria.

Finally, we look at elegance. Elegance as mentioned above, refers to the structure’s ability to create the maximum aesthetic possible. I, along with most everyone that goes to this stadium, would agree that the stadium is beautiful to look at. It stands tall and massive when you walk up to it, but it does not stick out in the skyline. When I got off at the Arsenal tube stop, I had to get directions to the stadium because I could not see it. The stadium emphasizes its massiveness for those that want to experience it, but does not do so in an ostentatious way. The stadium serves as an important symbol for the tradition of Arsenal as a powerhouse football club. The increased revenue from everyone attending this stadium has allowed them to sign better players and continue their dominance on the pitch. The stadium is a symbol for the powerful Arsenal team and is a meaningful place for every fan that attends it. With everything considered, I would argue that the stadium does meet the elegance standard.

Taking the three principles into consideration, the stadium almost passes the test of structural art. It meets two of the three requirements, but does not meet the efficiency criteria. This of course, was intentional. As mentioned previously, the goal of Arsenal was to make their new stadium a dramatic venue to symbolize their prominence in the world of football. Thinness and light form do not meet that idea. Architectural elements added to the stadium like facades out front and decorations adorning the structure serve that purpose. While the stadium is impressive from an architectural art perspective, it does not meet structural art standards.

Structural Analysis

Reinforced concrete was used for the flooring and framing of the first three levels of the stadium [1]. The lower, club, and box tier are supported by reinforced concrete rakers while the frame and structural steel rakers support the upper tier and level 4 [1]. The angle of a stand is known as the rake and the members used to support the stand are called rakers. The main stadium structure was able to be built at the same time as off site steel and precast concrete members [1]. Eight concrete cores are just inside the elliptical perimeter of the stadium to support it and transfer loads into the ground [1]. The stadium’s roof has 3,000 tons of steel and the entire stadium has 10,000 tons of steel throughout [6]. The stadium used 60,000 m^3 of concrete throughout the stadium [6].

The main concept of the structural system that is employed for the roof is actually a complicated version of a simple column and beam set up. This allowed the roof to cover fans while also keeping the view of the pitch unobstructed. The roof consists of three trusses: a primary, a secondary, and a tertiary set. A fourth perimeter truss also encompasses the entirety of the stadium. The length of the primary truss has a span of 204 m [1]. There are eight ‘tripods’ that transfer all of the vertical load to the columns.

Figure 5, Structural Components [1]

The load path of the roof is fairly simple once you visualize it as a beam and column structure. The tertiary trusses are in place all along the perimeter to help support the load of the roof and brace the primary trusses. The secondary trusses also help to support the roof and transfer load to the perimeter truss. The primary truss takes load from the tertiary and secondary trusses, as well as the roof itself and transfers that load to the tripods placed along the perimeter. There are also four additional tripods along the perimeter for stability reasons to make eight total tripods. Once the load has reached the tripods, it is transferred into the concrete cores and then into the ground.

Figure 6, Tripod

In addition to the tripods, there are props around the perimeter that help to transfer load down into the rakers. These props are responsible for getting the load from the perimeter truss to the ground.

Figure 7, Load Path of Primary, Secondary, and Tertiary Trusses on One Side

To analyze the structure and its load carrying capacity, we can model this structure as a truss. The analysis will be primarily looking at the primary truss. The simplified version of the truss is shown in Figure 8.

Figure 8, Truss FBD

The distance between each bottom connection is 14.5 m. The total length of the span is 203 m. This is not the exact length of the actual span but this allows a simpler analysis with the numbers involved. The load at each bottom joint signified by a blue arrow is equal to 10.4 tons [6]. The reaction at each end can be calculated as shown in Figure 9.

Figure 9, Solving for Reactions on Each Tripod

Another important aspect to consider for the analysis of this truss is the bearing stress that is induced on the tripod. The following calculations show the stress on the tripod. The radius of the pipe the truss connects to is 18 inches and the thickness of the pipe is 3 inches [6].

Figure 10, Bearing Stress

This means that the tripods need to be able to handle that amount of stress on the contact area it has with the primary truss.

A final set of calculations can be made for this truss structure, but it involves simplifying it even farther. If the truss, which only has loads on the bottom span, was reduced to a beam we can calculate the maximum moment occurring. To do this, we assume the same loads and reaction values that were calculated prior. From there we can solve for the shear diagram to get the maximum moment.

Figure 11, Shear Diagram

Using Figure 11, we can calculate the area of the first half of the graph that is positive to get the maximum moment. This value is equal to 3166.8 ton-ft. In calculating this number, it is obvious why the truss structure is braced so much. The bracing that occurs throughout this structure helps to prevent moment from deforming the truss. This extremely high moment value is definitely a large factor into the design conditions of the roof truss structure.

The design drawings were expressed well to Arsenal, even though there was not a firm need to. Populous had completed projects for Arsenal prior to this, so they were picked as the architects before a design was even in place. Of course, they wanted to do as best a job as possible so that they continued to receive work, but the initial design was not important. In terms of executing their vision, the break in construction as a result of the bank pulling their funding for the stadium was actually a blessing in disguise. With construction halted, Populous and Buro Happold were able to rethink parts of their building process and refine small details in their plans so that when the project started up again, everything would go smoothly. This was the case, as construction went on without any hitches when it started back up again.

Personal Response

It was a very humbling experience to visit the site of such a legendary and revered (or reviled if you are a fan of any other club in Europe) team. As a giant sports fan myself, I admittedly did not know much about the history of Arsenal before writing this blog. However, after talking to friends of mine it is clear why this stadium and team are so prominent in London and Europe as a whole. After reading about their accomplishments (and hearing from many salty friends) I better understand the connection this stadium has to Arsenal’s long history.

References

  1. https://issuu.com/jmurphy93/docs/dissertation_final-_emiratesstadium
  2. https://en.wikipedia.org/wiki/Est%C3%A1dio_da_Luz
  3. https://www.healthandsafetyatwork.com/arsenal-stadium-dump-truck
  4. https://www.boomtownbingo.com/history-emirates-stadium/
  5. https://www.unilad.co.uk/sport/internet-reacts-to-arsenal-winning-the-asia-trophy/
  6. https://www.designbuild-network.com/projects/ashburton/

Comments

  1. ndzanic3 says

    That’s pretty amazing that you were able to visit the stadium and find out not only about the history of the sports team but also to analyze the structure. As a soccer fan (of a team other than Arsenal-sorry) I think it would be so interesting to see the history behind the stadium as well as to be able to cheer on the team at the same place. Looking at whether the structure satisfies the economy aspect of structural art, I never would have thought to consider the source of funding and whether it’s privately or publicly funded. I agree with you that the private funding adds to the economy component. This blog post makes me want to go tour the stadium while I am here in London!

    • jgarrett39 says

      Haha no worries, I just learned about European soccer so I have no stake in any team. And yeah, I would love to go to a match sometime while in Europe. The atmosphere seems like no other in sports arenas around the world. The economy aspect of structural art for this stadium was definitely an interesting thing to look at, I was simply impressed that they could fund this stadium privately in comparison to how stadiums here in America do it.