Super tall towers are a sight to behold with undulating floors of steel and concrete rising high up in the sky. No city in the Middle East can vouch more for the love of skyscrapers than Dubai. But, such towering structures can be sustainable too, say architects Adrian Smith and Gordon Gill, who together are partners at AS + GG, an architectural practice based in Chicago.
The firm is the architect of the Burj 2020, one of the world's tallest commercial towers and the centrepiece of Dubai Multi Commodities Centre's (DMCC) new mixed-use district taking shape in Jumeirah Lakes Towers (JLT) in south Dubai. The architectural duo is also involved in the Kingdom Tower currently under construction in Jeddah, Saudi Arabia. Once completed, it will take over the mantle of the world's tallest building (1,000 metres) from Dubai's Burj Khalifa (828 metres).
The Burj 2020 is speculated to be around 700 metres in height when completed. "We will increase or decrease the tower's size according to the market. We are getting great feedback from people around the Middle East and GCC," said Smith. He was also involved in the design of the Burj Khalifa when he was working with Skidmore, Owings and Merrill.
"Cityscape 2006 was the first event we came to after forming our partnership. We got our first major project from Emaar which was the Burj Vista," he said.
Smith has been involved in the design of four of the world's tallest building in the world today. The two architects shared some of the challenges involved in designing and engineering tall towers at a media roundtable on the sidelines of Cityscape Global on Wednesday.
"One of the aspects of a super tall tower is that it is a science in itself. For architects and engineers, it is very different from doing, say a 50-storey building. Anybody can do a 50-storey building if they have some general experience in towers. The 300-metre mark is where you start going into the super-tall category," explained Smith.
The taller a tower gets, the more impact gravitational and horizontal forces bear on it. "If they are tapered, that helps. If they are stepped, it also helps. If they are straight up and down, that hurts. They will use more structure per square foot than if they are tapered or stepped," Smith said.
"If you manipulate the profile of the building, say by tapering it, the wind changes from floor to floor. It has less of an opportunity to organise across the building. Therefore, the forces are mitigated. That reduces the quantity of steel and concrete needed for the building," the architect added.
The architects said it is possible to make the buildings more efficient from a structural standpoint. "We are concerned about the embedded carbon in a building. Having a structurally efficient design confuses the wind. The building is then inherently more efficient and sustainable as it uses less concrete, one of the biggest carbon offenders," said Gill.
Another way to promote sustainability of the Burj 2020 District was to make it mixed-use. Besides offices, the project will also include homes, retail and hotels. "It's bringing a collection of people of varied interests into a space where they can live, work, entertain and practise their professions. One of the things the client talked to us about is to not just attract new tenants but to also have responsibilities to existing companies. The most sustainable way we could think of is to create a mixed-use community," Gill added.
"From an architectural standpoint, it is important for us to capture a family of buildings that operate together on a city scale. Dialogue among the buildings is essential." "We look forward to help the DMCC masterplan the district and buildings to be formed into a portion of the larger district that has already been completed. We want to form the seven buildings in Burj 2020 district, the podium and the base to be a family," the duo insisted.