Blog 3
Walkie Talkie

Walkie Talkie

Structure Information

Figure 1 – Picture by Me

Figure 2 – Picture by Someone Else

20 Fenchurch Street, known as the “Walkie Talkie,” was designed by Rafael Viñoly Architects and CH2M Hill structural engineers for Land Securities plc and Canary Wharf Group plc. This skyscraper, used as office space, residential space, and park space, has a really unique form—it curves outward on the front and back like a lens with an angled curve on the top (Figure 2). It’s pretty cool, especially when the building is 38 stories and 177 meters tall. This massive landmark began construction in January 2009 and opened in January 2015, being one of the newest additions to London’s skyscrapers. The Walkie Talkie is part of the booming skyscraper trend in the City of London (not “city of London,” but the confusing name for the smaller jurisdiction within the city), in the financial hub of the city. Even though it laser-beams cars (we’ll get to that later), this structure is a great addition to the skyline.

Historical Significance

This specific shape was unprecedented in skyscrapers when it was designed, and the shape is so unique that it has earned both praise and harsh criticism. With such a new building, the impact of the structure cannot be measured yet, but my guess is that it will inspire many architects and engineers to think outside the box in terms of form. I also think that the criticism earned by the building will motivate these designers be a little more conservative in design, still displaying new forms, but in a less exaggerated way. Outside of form and more on the engineering side, the unique cantilever approach (see structural analysis) used was basically custom-made for this building. Setting the core off center and cantilevering part of the curved façade in suck a specific way was extremely innovative, and we will have to wait and see if this technique gets adopted in other skyscraper designs.

Cultural Significance

The building’s culture impact is mainly through its divisiveness. The reception for the building has been very mixed. Many admire its innovative design and unique visual style, but the building is also hated by many for some pretty hilarious reasons. Besides some not enjoying the aesthetics of the skyscraper, many Brits are mad because it melts cars and causes wind tunnels, sometimes adding that it functions like “Bond villain tower.” If a building blew wind in my face and melted my car with a solar beam I wouldn’t like it either. The Walkie Talkie also affects the culture of the city through its environmental style. Along with various awards due to sustainable design, the building’s three-level park is an important fixture of the city. Although the park’s lack of complete public access is another point of criticism directed at the Walkie Talkie, this feature is still a positive.

Structural Art

In term of efficiency, this building’s structure carries complex loads extremely well. The architectural planning can be blamed for the poor performance in some areas (melting cars, channeling wind), but there have been no significant structural issues. Though the building is very new, and still must face years of trial, the efficiency required out of the structure

The whole point of this building is that it goes against what physics demands out of skyscraper form, and the result is poor economy. A tower of the same height could have been built with far less materials, so there is high cost is due to this over-the top design. Although this problem is due to the architectural design, it is impossible to say that this skyscraper minimizes cost for its particular function.

In the ideal of elegance, the Walkie Talkie building is difficult to measure. It succeeds in looking awesome, but using Billington’s concept of structural elegance shows that it does not succeed in this area. The visual aspects of the building were guided by architectural ideas, with the engineering just being done to ensure safety, and the load path is not on display.

Structural Analysis

One of the most challenging aspects of designing this skyscraper was that its architecture demands that its design is the opposite of a typical column. Columns carry gravity loads to the grounds, so a tapered shape toward the top is optimal, while increasing width toward the top is not preferred. The solution the team used was to set the concrete core of the building off center, since the building is heavier on one side, and also use perimeter columns of steel plate box sections. The loads travel downward through four main paths: the two outer columns of the inner core, and the two steel columns near the perimeter (Figure 3).

Figure 3 – Load Path

The distance from the core to the edge of the building range from 11 meters to 22 meters, and the solution was to have a max 18-meter span from core to perimeter column. Any beam distance above 18 meters is cantilevered. To get an idea of the forces present in these cantilevered, I calculated the forces in the beam with the longest cantilever, assuming simple supports (Figure 4). I named the weight per meter of steel beam w, the load transferred to the inner core column L1, and the load transferred to the outer column L2. Since max cantilever occurs just below the top floor, these loads are due to the slab and roof above.

Figure 4 – Cantilever Calculations

The calculations show that By is always supplying a positive force, but Ay only supplies a positive force if L1 > 52.6w. As the cantilever length decreases going down the building, L1 increases while w decreases, showing that the support in the inner core column increases significantly moving toward the base of the tower, due to both the weight above and the cantilever length.

The geometric changes at each floor demanded advanced technology to communicate the design and construction of the building to those outside of the design team. To tackle these challenges, advanced 4D-BIM modelling—3D building information modelling with time added as a fourth dimension—was used, allowing the team to anticipate challenges and maximize safety. This information was mainly used to communicate the building’s program with the clients and mitigate communication issues with the construction team.

Personal Response

The Walkie Talkie Building was only ever slightly impressive to me until I got up close. The first time I visited London I didn’t really give it a second thought. I thought it was a slightly cool building that was probably very difficult to build. When I stood under the amazing vertical curvature of the building, though, I was blown away. It was pouring rain, but standing in front of the building kept us out of the rain. Looking up, it looked as if though the building should be falling on top of me, and the curvature makes the building appear even taller than it really is. As a bonus, I also learned that the top of the building has a full park, which I would love to check out. Overall, I think this is one of the most visually impressive structures in the world with some very impressive engineering that allows a really unique form. 

References

[1] https://www.steelconstruction.org/design-awards/2014/commendation/20-fenchurch-street-london/

[2] https://www.telegraph.co.uk/business/2017/07/27/walkie-talkie-building-sold-hong-kong-company-record-128bn-deal/

[3] https://www.steelconstruction.info/20_Fenchurch_Street,_London