Blog 1
Coda Building

Coda Building

Structure Information

The new Coda Building began construction in 2016 and is expected to be completed in the 4th quarter of 2018 [1]. It is located in Midtown, Atlanta, just one block from Tech Square. Georgia Tech and John Portman & Associates announced their plan for the 750,000 square foot collaborative building and high performance computing center. 620,000 sq.ft. of the building will be office space, half of which will be available for companies and the other half will be occupied by Georgia Tech. There will also be 40,000 sq.ft. of retail space, which includes the historic Crum and Forster building, labelled as 1 in Figure 1 and in the foreground of Figure 2. and 80,000 sq.ft. of a data center, labelled as 2 in Figure 1 [1]. The building plans to offer an “unparalleled collaboration between research and industry” by giving major companies associated with Georgia Tech the opportunity to work closely with Georgia Tech and with each other with access to a high performance computing center and interactive community space. FS2 was commissioned for designing John Portman & Associates’ 21-story building [3].

Figure 1. Overall Picture [1]

Figure 2: The Historic Crum and Forster Building

Historical Significance

The Coda building itself embodies many state of the art design aspects.There are 5 stories of parking located below the building. The parking deck was put in place using a boring machine and soil nailing. Laser scanning has been used in every phase of construction and by plotting exact points, the scanner was able to catch that one wall was leaning a few inches. The soil nails were redone and this was taken care of thanks to the newly practiced laser scanning technology. The building is also the first ever in America to have TWIN elevators. The TWIN design has two elevators running at the same time in one shaft [3]. Because companies may have multiple floors, this permits someone who is going from floor 17 to 15 to hail the top elevator, instead of sharing with the lower floors. There is a holding place for the elevator at the top and bottom of the shaft so the elevator can go from the top floor to the bottom floor without being blocked by the other elevator in the shaft. The elevators can work with varying floor heights (i.e. a taller lobby) and go to any floor, without separating even or odd floors [3].  The difference is, passengers enter their desired destination upon hairling the elevator, so the paths and elevator can be selected in advance[4]. Initially, the building design had a low rise/ high rise solution, which required a physical barrier separating the lower and upper floors. This solution fit the requirements, but not the collaborative goal of the building. With the TWIN elevator system, the building can remain one part and keep the connection between the upper and lower floors [3]. More than 200 buildings around the world have implemented this elevator made by Thyssenkrupp, including their headquarters in Essen, Germany [1]. There have been many other collaborative spaces constructed and loads of research done on the topic, but the Coda building combines many different practices from floor plan to structural design. Other complete examples include Oregon’s Collaborative Life Sciences Building, the Bacardi headquarters, and the Hyundai Campus. Many of these buildings embody similar approaches to collaboration including open, connected spaces with natural lighting and open floor-plans. They strive to inspire with their spaces and promote the Green initiative [5]. A key difference is a few companies find that being in a suburb increases motivation and productivity compared to urban campuses [5]. The Coda building will definitely inspire future buildings. It is the newest example of a collaborative building, with innovations that are appearing for the first time in the US. Once complete, the Coda building will be the “thing to beat” as others aspire to create collaborative, innovation driven spaces. From design to furniture selection, Coda will have state of the art technology and research in every detail.

Cultural Significance

The Coda building will house both industry professionals and GT research and extend Tech Square. Over the past few years, Tech Square has become the innovation hub of the southeast and, with Coda, it will have three million square feet of commercial space attributed to it [3]. The use of new technologies in the building and collaboration spaces with researchers and professionals in the Coda building will add fuel to the innovation fire currently in Tech Square. The building will also have public spaces, an interactive media wall, and retail spaces for the public. The historic Crum and Forster building will be updated and accessible to the public as a gathering place and outdoor living room [1]. President Bud Peterson discussed how the collaborative building will also have a positive impact on Midtown by bringing people together in “a mixed-use community of innovation, education, and intelligent exchange.”

Structural Art

In regard to the basis of structural art, economy, efficiency, and elegance, the Coda building is very lacking in the first. There were no major monetary constraints, which violates the basic principle structural art, that creativity is fueled by the monetary constraints (economy). The historic building has features pre-dating the era of structural art and is not tall enough to be considered structural art. The Coda addition does embody some features of structural art including clear load path because it is a glass building and the beams are visible. Only necessary supports were used, but they were not always the most cost effective options (efficiency). The single beam support of the staircase and pop-out section of the building are examples of this. Also, by omitting beams through the walkway and having the large open space below, large expensive supports were needed to hold the structure up during construction, until it was tall enough to be stable. See Figure 3, Figure 4, and Figure 5 for the temporary supports and after removal.

Figure 3: Base of Temporary Support

Figure 4: Top of Temporary Support

Figure 5: Remanence of Temporary Support

Elegance is satisfied in the engineering sense as the supports and load paths used are visible and the engineering systems are innovative and impressive, although not affected by monetary constraints. The main focus of this building is aesthetics and that is it’s fault in structural art. In regards to scientific, social, and symbolic aspects of the building, Coda does a better job than compared to the E’s. Scientific is where the building is lacking, as the design and materials are not constrained by money, although the structural design is creative, clear, and safe. Socially, as I described in the cultural and historical sections, Coda will have a major impact on the innovation world, the workplace, Midtown, and future buildings. There are not many long term costs to society, and, as a privately funded building, there are not short term monetary costs. There are, however, short term costs in the noise and road closures. Symbolically, the building creativity and public gathering spaces embody the aspirations of the building, collaboration and innovation. Even the research and innovation being done within often does not have monetary constraints, so the building symbolizes the uses perfectly. Overall, Coda cannot be considered structural art because of the basis of creativity with economic constraints. The building cannot be compared to other examples of structural art or explained with the E’s and S’s other than economic because they all have a basis of monetary constraints.

 

Structural Analysis

The Coda building was designed to embody collaboration and innovation in every aspect. The staircase and pop-out side of the building are examples of structural innovation and the glass shows the connection and openness within the building. The speed and precision of construction shows how innovation and collaboration are being applied. Boring down five levels and using soil nailing while pumping out and lowering the water level below is almost unheard of. Forms and concrete pump trucks are adding floors constantly with a crane on site 24/7 to move the forms once the concrete has solidified. While concrete is forming floors, other sections of the building are getting the steel frame put in. The two sides of the building joined at the staircase are going up simultaneously with the crane in the elevator shaft because from there it can work with and reach both. These are just a few examples of how every aspect of the building embodies collaboration and innovation.

The systems I will be analyzing are the staircase and the pop-out section of the building. The design load of an office building is 50 pounds per square foot per floor, although the measured load is only 10.9 pounds per square foot. The staircase goes from a line load from the roof through the walls, to a surface load of the floor, to a line load in the walls below and so on down the building until the surface load on the bottom floor is distributed into a point load in the single column to the ground as seen in Figure 6, Figure 7, and Figure 8. The glass panels around the staircase are shortened to account for the curvature. Assuming the windows are a foot wide, the diameter would be 12 feet. The stress would be the force over area. Force equals the number of floors (7) times the area (pi*6^2) times the force per square foot per floor (50) divided by the area (pi*6^2). The stress calculation for the floor above the column gives a stress of 350 lb/sq.ft. (1). The stress in column is the force (same as above) over the area of the column (pi*2^2). The stress calculation gives a stress of 3150 lb/sq.ft. (2). I am neglecting the self weight of the pole in this calculation because it is negligible. I found the diameter by comparing to the people standing by the pole and the windows. The critical buckling is (pi^2*E*I)/L^2. Assuming E is 7250 ksi (that of strong concrete, have to x12x12 to get feet), I is ¼ (pi*R^4), the height is 25 feet,  the critical buckling point is 207,171 lb, which is much greater than the P of (3150*A) which is 39,584lb. The change in shape (delta) is (P*L)/(E*A). In this case, delta is .075 feet. This could be explained in drawings by showing how the force over the whole area of the staircase/ room is initially distributed then all on one point, the column, therefore it is very large and requires such a thick column. The drawings would show the detailed supports that transfer the load to the column and how they connect.

Figure 6: Stairwell Load Path [1]

Figure 7: Process of Stairwell

Figure 8: Future Completed Pedestrian Walkway

The pop-out section of the building is a cantilever with 18 floors. The load goes from the roof, down as a line load to the floor below for each of the 18 floors above the overhang. From the bottom of the overhang, the load is transferred through a fixed connection, like a cantilever, to the main structure of the building. Refer to Figure 9 to see the load path.  Assuming each window is 3 feet wide, the side length is 25.5 feet and the width is ¼ of that so 6.375 feet. Therefore, the force on the cantilever is 50 pounds per square foot per floor *18 floors * 25.5feet * 6.4 feet, which equals 146,310 lb. Assuming there is one beam supporting each side and even distribution, each will hold 73155 lb total, which results in a w of 5852 lb/ft (73155 lb/25ft/2). Assuming the beam is 2×1 with the long side on top, the deflection is (wL^4)/(8EI). Assuming L is equal to the side length of 6.4, E of steel 29007*12*12, and I is of a 2ftx3ft beam (as observed in Figure 10), the deflection would be 0.14 feet. Fx at the base would be 0, Fy would be w*l 33650lb upward, and M would be 3.2ft*33650lb (107700 ft.lb.) clockwise. With this information you could explain the design by showing that a thicker beam will not break and that a heavier base will ensure the cantilever does not tip (i.e. a toothpick will break trying to hold a weight but a pencil would not, the pencil in an eraser would tip over but in a wall pencil holder will not) and explain how the force requires a thick beam and the building can hold the rotation caused by the force. The drawings could show exactly how to attach the beam and it’s dimensions.

Figure 9: Cantilever Load Path

Figure 10: Cantilever Process

Personal Response

Having been in the building, I learned a lot about how much more complex the construction activities are and that you never know what is going to happen. Very often on sites, unexpected bumps in the road are hit, causing delays. In the Coda case, the water continuously had to be pumped out to bore the parking, 24/7 for weeks. I also had never realized what it took to have large gaps and how expensive adding a truss instead of columns is. Material wise, it seems the truss is equal, if not better. However, on the construction side you see the semi-permanent, expensive to get and install, time consuming supports and scaffolding needed to hold the load until the truss is complete. In design classes and in final presentations or books on buildings, details like this are often omitted.

Resources

[1]http://www.news.gatech.edu/2016/04/20/georgia-tech-portman-announce-coda-tech-square

[2]https://archpaper.com/2018/01/georgia-tech-atlanta-coda-technology-jobs/#gallery-0-slide-0

[3]https://www.fs2ec.com/coda-in-tech-square

[4]https://www.wired.com/2016/05/thyssenkrup-twin-elevator/

[5] https://www.gensler.com/design-forecast-2015-the-future-of-workplace

 

Comments

  1. ndzanic3 says

    I visited the Coda building as part of a class field trip, but the noisy construction site made it difficult to hear a lot of the information said about the building. It was really interesting to read your blog post about it and learn new facts about the building as well as the structural analysis. Especially exciting is the twin elevators because I think every tall building should have these to maximize efficiency! You said that the building is not tall enough to be considered structural art, but I do not remember reading any mention of height requirements for structural art in David Billington’s book.