How Tall Can You Make A Building?

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18 Jan. 2020. In the past, high-rise tower blocks got a bad rap. Architects on the residential side of the equation got flack for creating buildings that piled thousands of people into a small space and expected them to all live together in harmony. And commercial builders were hated by environmentalists for the energy use of modern, multi-story office buildings.

Things, however, are changing. The need to avoid urban sprawl and protect the natural world now means that builders are going upwards to save on space, but how high can they actually go?

Over the last twenty years, we’ve seen numerous records shattered. For around 25 years, the Sears Tower in Chigaco was the tallest in the world, rising higher than even the Twin Towers in New York. Then a taller building went up in Kuala Lumpur, followed by Taipei.

Dubai then put itself on the map by smashing the previous record, building an 818 m behemoth called the Burj Khalifa, more than twice the height of the already-impressive Empire State.

The question for builders now is whether it is possible to go even higher using existing technology. Finding a crane for sale capable of such a feat isn’t the hard part. Neither is finding materials that are strong enough to support such massive structures above them and cheap enough to make them economical.

No – the challenge is something seemingly less monumental: creating the internal transportation system.

A building that is 1000m tall is a kilometer long. On the flat, that is a long way – several city blocks. In the air, it is even further because of the difficulties of going up and down.

Top structural engineers know that if they want to create usable, ultra-tall buildings, they need to upgrade the transportation system.

It isn’t just a matter of making lifts that travel faster – though that is a part of it. It is also about the space that lift shafts take up.

As a building grows taller, the demand for internal transportation rises. The number of lifts required increases at an exponential rate, making it difficult for engineers to cram all the transport services that they need into the core of the building. Eventually, you end up in a situation where you need more lifts that the physical footprint of the building allows, just to service all the floors.

Engineers think that they could go twice as high as the Burj Dubai using “buttressed core” technologies. Buildings as tall as 1,600 meters are technically feasible with current-generation construction technology. But servicing those buildings is a big problem. You could end up in a situation where nobody wanted to rent the higher floors, simply because getting to them is so difficult.

If there are no improvements in lift technologies, then supertalls may evolve in a different way to skyscrapers of the past. Builders might design them for the ultrarich, reducing the population density of the buildings and opening them up for residential space. We already see this happening in the environs of Central Park in New York, but it is a trend that could spread all over the world.

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