Blog 2
Go Arsenal! (Emirates Stadium)

Go Arsenal! (Emirates Stadium)

Figure 1: Me in front of Emirates Stadium

Structure Information

Emirates Stadium was completed in 2006 and is located in Ashburton Grove, London [1]. The stadium is used for the Arsenal Football team’s home games. The structural engineer for the project was Buro Happold [2]. Funding for the stadium came from loans from many banks given to Arsenal Holdings plc, Granada, Nike, and sales from the land that was not needed for the stadium. Additionally, Emirates Airline paid £100 million for a 15 year sponsorship of the stadium as well as an 8 year sponsorship of team uniforms [1].


Historical Significance

A newer technique for creating steel parts was used by the steel contractor to insure the accuracy of the parts. The method included creating three-dimensional models of sections from individual X-Steel models to be used in manufacturing of the steel. The three-dimensional models could be rotated and moved in order to create the most accurate version of the parts for the stadium.  [2]

Other than this, the stadium was built as a typical football stadium, with the roof allowing sunlight to hit the field while also keep the sun or rain off of the spectators. Since the roof is not connected to the seating, there is also airflow to keep the stadium cooler without the need for air condition. What sets Emirates Stadium apart is that the stadium is an ellipse shape, rather than a rectangle, which is more common for football stadiums. [1]


Figure 2: Development at Past Stadium for Arsenal [2]

Cultural Significance

The stadium is situated inside of a 7.8 acre park, which is open to the public. Additionally, Arsenal built houses and other buildings around the stadium for the surround communities. The location of the stadium allows for access from the London Underground and helped push for improvements at the Holloway Road station and promotes politicians to obtain funding for improvements at two other stations. Arsenal also sponsored the conversion of their past stadium into apartments, student housing, a garden, and health centers. [1]

 

 


Structural Art

When looking at the roof of Emirates Stadium from inside, outside, and especially from Google Earth, the stadium, this structure displays structural art very well. The arched trusses that hold up the roof and the connection points of the roof to the elements holding the roof up are all visible and easy to find. The load paths are visible, and the structure looks light. Additionally, efficiency and economy were highly considered in the structure. Steel tubes were specifically chosen for the cost and efficiency, as well as the constructability.


Structural Analysis

The roof of Emirates Stadium is made up of polycarbonate and steel tubes [1]. Steel tubes were chosen for cost and weight purposes, as well as constructability since less surface area means less detail in the steel manufacturing process. The girders were built off-site in pieces and assembled on-site. Temporary structures were used until all of the trusses were put into place with cranes so that there was no deflection from the self-weight of the trusses. [2]

The roof consists of the polycarbonate covering and many trusses, varying in size. There is a circular truss around the perimeter, truss beams, and truss girders. Additionally, there are 8 tripod columns to stabilize and take loads. All of these parts work together to create a stadium roof that does not touch the seating area and draws the viewer’s eye to the pitch, rather than the roof [1].

The load path goes from the roof up to the smaller, triangular truss beams, up to the larger truss girders. The two secondary girders transfer the load to the two primary girders. The primary girders then transfer the load to tripod columns. A circular truss around the perimeter of the roof is attached to the roof and provides support for the beams. It also transfers load to the tripod columns, seen in Figure 3. There are also 64 props around the stadium to help transfer the load down [3]. All of the beams and girders can be seen in Figure 4, a bird’s eye view of the stadium. From the inside of the stadium, the load paths from the secondary and primary girders, as well as the columns can be seen (Figure 5). From the outside, the tripod columns can be seen connecting to the roof (Figure 6).

Figure 3: Load Path from Top View [6]

Figure 4: Tripod Column from Inside Stadium

 

 

 

 

 

 

 

 

 

 

Figure 5: Load Path from Inside Stadium

Figure 6: Load Path from Outside of Stadium

The primary girders span 204 m and the secondary girders span 100 m, with the 32 beams varying in size. The girders cross section is 15 m deep and 10 m wide. [2] The polycarbonate roof covers 27,200 m2 [4]. All of the steel on the roof weighs 3,000 tons [1]. The total weight of the roof is about 41,510,000 N [5]. This means that the average area load of the roof is 1,526 N/m2.

To idealize the roof, we can say that each beam takes the same amount of load. Figure shows the idealization schematic. The force from the roof that each beam takes is calculated by multiplying the area load by the area divided by 32. The load for each beam is:

The loads of 6 of the beams go to each secondary girder, meaning each secondary beam has 6 point loads and reactions the ends from the primary load. Due to symmetry, the reactions are equal and there are no forces in the x-dimension. Figure shows the free body diagram. The reactions are:

The loads from two reactions of the secondary girders and the loads from 10 beams are on the primary girders, seen in Figure . As with the secondary girders, there are no forces in the x-dimension and the reactions are equal. The reactions on the primary girder are:

The maximum moment in the primary girder is in the center, while the maximum shear force is right next to the reaction. Assuming the distance between the beams are all equal to 16 feet and the distance between the secondary girder and perimeter is 30 feet, the maximum moment is:

This very large maximum moment is one of the many reasons why a triangular truss in the shape of a moment diagram was chosen for the primary girders.

The design of the stadium included a huge development of the area around the stadium in addition to the stadium. Because of this, the elliptical shape was chosen since it meant that the closest residential building was over 100 meters from the stadium. Models of all of the initial designs were presented to stakeholders, and once a shape was chosen, a full model including the neighborhood was presented. [3]


Personal Response

I really enjoyed visiting Emirates Stadium. Researching it more and going into the structure was very interesting. The stadium is so massive! I didn’t even really realize at first that the roof wasn’t resting on the seating area, but when I did, I was so amazed at the structural engineering.


References

1 https://www.designbuild-network.com/projects/ashburton/

2 https://www.steelconstruction.org/design-awards/2006/commendation/the-emirates-stadium-arsenal-football-club/

3 https://issuu.com/jmurphy93/docs/dissertation_final-_emiratesstadium

4 https://www.independent.co.uk/student/magazines/emirates-stadium-new-goal-for-the-gunners-5331573.html

5 http://www-civ.eng.cam.ac.uk/cjb/schools/stadium/silcock_files/S2%20Emirates%20structural%20analysis%20Teachers%20Notes.doc

6 Google Earth

Comments

  1. I think this stadium is definitely structural art as well. From the outside especially, the only non-structural feature is the glass, which doesn’t take away from the lightness of the design. It’s also amazing that the roof isn’t resting on the seating. Really cool building, I would love to visit it too sometime.

  2. etripolitis3 says

    I really liked how detailed your load path is. This stadium has a really interesting path. I would also be really interested in how the seats load and load path work. They must have huge beams to keep such a big overhang! Makes sense though since the point of the stadium is the views.