12 apr 16 | Curbed
Supertalls and Sustainable Skyscrapers: Architect Adrian Smith on the Mile-High Building
by Patrick Sisson
On the continued pursuit of the world's tallest building
When you’re the architect who designed the tallest building in the world (the Burj Khalifa), as well as the under-construction skyscraper (the Jeddah Tower) that will one day claim the title from your previous work, it would seem that you would be able to relax. But architect Adrian Smith, who along with his partner, Gordon Gill, have formed one of the pre-eminent architecture firms with expertise designing ever-taller towers, knows there’s no time to stop. Not only has a new building in the planning stages, a proposed observation tower in Dubai, set its sights on the record, but Smith, who just won the University of Illinois at Chicago’s Legacies and Leaders award, knows that thresholds in tower design tend to be temporary. From his work as a young architect as part of the Skidmore, Owings & Merrill team that designed the pioneering John Hancock Center in Chicago, to his design for the kilometer-high Jeddah Tower, he's seen strategies change, and but still believes that supertall structures represent more than an engineering achievement: they "can be a symbol of success and optimism for the future of any city." Curbed interviewed Smith about his career, new projects, and why he believes supertalls can be not just a symbol, but a sustainable part of the future.
How has architecture’s understanding of, and ability to design for, wind changed, from the Hancock Center, which you worked on, to the Burj? What are the advances, and future developments, in technology and design allowing you to design better, taller, windresistant
"The has been a tremendous advance in the understanding of wind forces since the time of the John Hancock Center. At that time, very little was understood about the acceleration of movement caused by vortex forces on tall building design. One could observe this by seeing the chandeliers moving and the toilet water sloshing during high wind conditions. Interestingly we have found that there are many benefits to shaping the tower to avoid the wind forces. For example, in the case of the Pearl Tower design in Guangzhou, we found out that the wind was coming from predominately the same direction almost all of the time, so from the start, we oriented and further shaped the tower to take maximum advantage of this. The openings we created not only added the benefit of shedding the vortex forces on the building, it was cost effective by saving structural material in the process. Another benefit was that we designed the openings in the building for wind turbines, and they generate power even in very low wind speed conditions. Technically speaking, the precision of wind testing and CFD modeling software is allowing us to be more precise in understanding the wind loads on tall structures, and where the most accurate place to incorporate turbine is."
How much stronger is the force of wind when you’re, say, at the top of the Burj?
"It really depends on the location on the building, however, the higher the tower, the greater the force of the wind impacts the structural design of the building, since all buildings are essentially cantilevers extending up from the ground."
How is technology not just making skyscrapers taller, but better places to live? I see something like the Shanghai Tower that offers not just height, but strives for a more sustainable, green way of life for those that spend a lot of their time in the tower.
"A supertall tower can be a good place to live. But I see them more as a symbol for the entire city – not just for the people who live in it. Developers are now realizing that if they own the land around the tower, they will benefit from building the tower. Highdensity towers tend to attract other density, which in turn creates value. Right now we’re seeing in China, Dubai, and in other places, scenarios where the developer is building and looking at the entire area, which is much larger than the tower itself. Tall towers significantly increase the value of the land and buildings around them—residences and businesses that have views of beautiful towers increase drastically."
"This happened with the development around Burj Khalifa in Dubai. People occupying buildings around the Burj are paying significantly more for the units with views of the tower, which has made that overall development highly profitable for Emaar Properties in Dubai. Jin Mao Tower in Shanghai is a similar example. Technology in elevator systems have made living in new towers more efficient, engineering of exterior walls have made living in most buildings much more comfortable and allowed for greater views and better natural light levels within occupied spaces, well designed structural systems for tall structures have made living in tall towers more healthy as has better mechanical engineering provided cleaner air quality for interior spaces. It is yet to be seen that the Shanghai Tower will improve the quality of life for its occupants than well designed shallow double wall systems at a fraction of the cost."
"The supertall tower can be a symbol of success and optimism for the future of any city. If cities don’t continue to build and improve their conditions, they will usually go into decline. Sheikh Mohammad wants to really create a worldclass city. He wants Dubai to be
important like New York, Tokyo, Hong Kong, or Shenzhen—and he wants it to be diversified. It takes all of these components to make a great city. I think the visionary leaders are saying, 'Build it right and they will come,' and Sheikh Mohammad is proving that right now, at least, he has over the last 10 years."
What’s your favorite picture or image of the Burj, either taken of the building, or taken from the building, and why?
"Almost any picture taken of the tower in the early morning or late afternoon when the sun is shining will look great because of the glistening skin and shape of the tower. When the clouds are low, it's very interesting to photograph the shadow of the tower on the clouds from above the clouds."
Can you discuss the design for the Greenland Tower Chengdu, specifically how the glacier-inspired shape interacts with the wind?
"The architecture and structure work together, fully considering the structural requirements of supertall buildings in a high seismic zone, using a geometrical plan, a tapered form, and a highperformance bracing system to ensure the structure’s stability and efficiency. The tower form has superior aerodynamic performance due to the fact that the tapered faceted cylinder geometry efficiently disrupts the wind, ultimately preventing large vortices from shedding in a coherent pattern, reducing high inertial wind loads. MEP and other systems are designed with highefficiency sustainability features, creating a new generation of the highperformance supertall buildings."
Is it curious, and maybe a bit ironic, that construction of these incredibly tall buildings can be limited by the capabilities of elevators and transportation systems as much, or more, as other engineering challenges? Have you figured out the elevators system for the Jeddah Tower, and how will it work?
"The introduction of the flat cable on the elevator systems for Jeddah Tower reduces cable weight and allows us to go higher with express shuttles than ever before. Higher strength materials are helping to make the tall tower more efficient and precision monitoring of completed structures to better understand their actual behavior is improving our engineering predictions in the design process."
What were the limiting factors that stopped you from designing the Burj Khalifa to be any taller? What about the Jeddah Tower?
"Both the Burj Khalifa and Jeddah Tower could have been taller, but we were restricted by land and client budget. In each case though, the client’s goal was to be the world’s tallest building at the time of completion of construction."
The Kingdom Tower is an evolution of the threepronged, palminspired design of the Burj; is this the best way to design buildings of increasing height, or are there other layouts/schemes/shapes you’ve been experimenting with buildings of this extreme height?
"I believe that eventually we will have very tall structures that are linked together with sky bridges so there can be pedestrian connections between buildings at several different levels. These bridge levels would also act as structure to help provide lateral bracing of these mega structures. It is possible to do now, just not very economically feasible. We have proposed this on our 1 Dubai and Chengdu satellite city concepts."
"We have been working on the possibilities of a mile-high tower for about five years, and we know that it is possible with current technology. The tower would integrate several sky bridge platforms for circulation and structure. I think that for those of us who like height, these buildings would be exhilarating. We will keep pursuing the vision for research purposes until a special person wants to explore the possibility and has a great site in mind to see something magnificent get built. All it takes is the will, the means, and the time to see it through!"
You may have the unique position, as a firm, of designing two of the tallest buildings in the world; just as there are a few firms that can design buildings this tall, are there only a few contractors who can build a megatall structure?
"Actually, I have designed several supertall towers that would have been the world’s tallest if built (7 South Dearborn in Chicago, 1 Dubai, an early scheme for Samsung Togok in Seoul, a Las Vegas mixed use project and Wolf Point in Chicago, just to name a few). It's one thing to design a supertall but it's quite another thing to get them built. It takes a full team of experienced professionals who understand the issues involved in both the design, technology, engineering, wind and soil testing, and the many facets of constructing a supertall. Most importantly of all, it takes a client with access to the incredible financial resources, real estate knowledge and marketing skills needed to accomplish the task. I have been very fortunate to have been commissioned by two such clients."
Your firm is just as known for sustainability as it is for supertall construction. Can you talk about your designs for Expo 2017 in Astana, Kazakhstan, and the Third Industrial Revolution concept for energy efficiency and generation?
"A significant part of the energy consumed by the expo community will be provided from renewable sources. Buildings are designed as generators of power and their energy will be used or stored using innovative technologies while being distributed by a smart grid. The forms and language of the buildings are designed to reduce their energy needs and operate as ‘power plants’ that harness energy from the sun and/or wind. The buildings will use this power directly or supply it to the districtwide smart grid for storage or use. The expo community will also provide the infrastructure to encourage and support the use of vehicles that use renewable fuels."
"Within the general energy theme of the exposition, the overall aim was to reduce the energy demand of the site to the greatest extent possible using both passive and active strategies. At the same time, opportunities for generation of power have been investigated and incorporated into the building design. Examples include highperformance glazing that maximizes solar heat gain in winter, but also provides shading in summer. Energy piles will be used to reduce energy demand and to provide temperature modulation within the atria during winter."
"The sitewide infrastructure concept, developed by the design team, is an integration of occupants, buildings, and utilities. A smart-energy grid, a smart recycled-water grid, an integrated waste management system, and an interseasonal underground thermal energy storage have been developed with sustainability goals that include peak and total energy demand reduction, water reduction, and waste-to-land-fill reduction targets."
"Other goals that will be met for the site and buildings include energy storage capacity that can meet two days of emergency demand; 100% of rainfall from a 100-year storm event will be managed on site; and 90% of waste generated on site will be diverted from a landfill."
Considering your firm’s work on the Chicago DeCarbonization plan, and its findings, especially that the tallest, most efficient building was a threestory walk up, how do you see taller buildings figuring into the future of cities? What roles do they play in addition to being icon that may become magnets for development and investment?
"That was the conclusion that was reached in an ongoing study on density that our firm is still working on. We’ve come to different conclusions using different models. When including in the concept of preserving open space, the three story walkup doesn’t add up. I truly believe that supertall buildings are inherently sustainable, first and foremost because of the issue of land use."
"Simply put, supertall buildings foster the opposite of urban sprawl. Within a desert environment, urbanization is even more important, given the energy and efficiency loss of all systems associated with covering large stretches of land. Building enclosures are also reduced when a building is tall. Imagine a typical 250 meter tower with around 48 floors like FKI Tower. It obviously has one ground floor and one roof in addition to the four surrounding walls. If you split this building into 16 buildings of three floors, you will have to add 16 ground floors and 16 roofs where energy loads will be added. It’s pretty clear, when you think about it this way, that the energy efficiency of a supertall building is superior to the equivalent number of low-rise buildings."
"And if you did build those 16 low-rise buildings, think of the additional land that would be paved over in the process, and the attendant infrastructure—roads, power grids, water and sewers, and so on—that would be necessary to service all of that sprawl. Particularly in terms of land use, building tall makes tremendous sense. There are only two issues where tall structures lose out to threestory walk ups. First is the efficiency of structure, and the second is the embodied energy of each building type. Tall towers are usually only 70-80% efficient because of elevator demands, mechanical shafts, stairways, corridors and increased size of the structural components. Towers are made of concrete and steel, walk ups are made of wood."