Even as architects face fewer technical constraints, the design and construction of a supertall building remains definitively complex. Fixed constraints, including cost, schedule and program, must be reconciled with the more subjective aspects of design – a fluidity of aesthetics, culture and experience.
Standing at 300 meters or more, the supertall requires the architect to anticipate the effects of even the smallest permutation. By changing one detail of the façade, the building’s overall construction cost could jump significantly. A one-meter extension of the building footprint can intensify the dead load beyond what the structure can withstand. Even a minor change in floor-to-floor height can elevate steel or concrete costs and effectively confine the project to the drawing board.
Shanghai World Financial Center
Commissioned by the Mori Building Company, the Shanghai World Financial Centre was to be the tallest building in the world. After two years of design and planning, there was a sense of confidence that construction – nearly a 10-year long process – would proceed smoothly.
A change request came just after 200 foundation piles were driven into place – Mori wanted a taller building – which, based on current practice, would result in a heavier building. Though, in other circumstances, KPF could have revised the design to achieve additional height, in this case the foundation that had already been partially laid would not be able to support it. So KPF and engineers from LERA replaced the existing structural system with a new diagonal-brace frame and outrigger truss system. The new structure – though 32 meters taller – weighed 10% less, enabling, among other things, the reduction from 17 wide exterior columns to just three narrow ones. In the end, not only did the building cost less, but the redesign also expedited construction time.
Efficiency is a theme that permeates the tower. Unlike many supertalls that lose as much as 30% of their floors to unoccupied vanity height, the Shanghai World Financial Center surrenders just four.
The resulting silhouette of the Shanghai World Financial Center is impossible to mistake. Although it was the world’s tallest building for only a few years, the building endures as one of the city’s most beloved landmarks and destinations – even reincarnated as a popular tourist souvenir found in the building’s gift shop.
Smart Urban Density
At the start of the 20th century, the global population was just 1.6 billion, a mere 20% of the 7+ billion people on Earth today. Population growth fuels urban migration and the world’s cities are quickly densifying. New residents cluster in high demand locations that offer robust infrastructure and convenient services.
CITIES HAVE A NEGATIVE REPUTATION FOR BEING EXPENSIVE, DIRTY, AND UNCOMFORTABLE.
According to Harvard urban economist Edward Glaeser, density is not bad. In fact, he says, “density matters because we’re a social species geared to learn from people around us.”
Glaeser argues that we cannot underestimate the value of face-to-face contact. We become smarter by being around other smart people “and that’s why cities thrive.”
With so much of the planet steadily densifying, vertical construction – going up instead of sprawling out – offers a viable solution to accommodate growing populations and cities. According to the UN, there are 200,000 people moving into cities every day. From a practical standpoint, skyscrapers increase the planet’s inhabitable surface area. Stacked buildings allow more people to live, work, and play on the same piece of land.
A supertall acts as a ballast in its city – the most notable building along a skyline of notable buildings. Its height marks a visual presence from a distance, but also plays a part in determining a city’s growth. A meaningful connection between the base of a supertall and its urban fabric advances societies by attracting new people and businesses.
International Commerce Centre, Hong Kong
A supertall is subject to the same concerns and demands as those of a small city. Completed in 2010, the International Commerce Centre (ICC) in Hong Kong houses the activities and functions of tens of thousands of people. For such a significant addition to Hong Kong’s city fabric, the building is at its best because it is frictionless.
There are 30,000 people who enter the ICC every day. And they enter all at once. Without carefully designed circulation paths and lift systems, getting to one’s destination could become an all-day journey. Because the building seamlessly connects to Kowloon Station below, the individual commuter feels no resistance when moving from underground, to ground, to the building’s highest levels.
Set against the strong winds sweeping off Hong Kong Bay, the building’s profile maximizes leasable floor space without creating extra wind resistance. The building’s re-entrant (notched) corners provide the building with the same wind efficiency as circular floors, but without the hard-to-use round floor layouts.
Emulating its circulation patterns and wind-efficient form, ICC’s construction was staged to provide the least amount of resistance possible. Clocked at a typical speed of five years, supertalls require a huge amount of upfront investment that show no return until the building’s floors are leased. Curtailing this timespan, ICC’s vertical organization allowed for full occupation of the lower zones, while the middle and upper zones were prepared for fit-out and still under construction.
How Far Up?
Even when a building features a transcendent design, the true mark of a building’s timelessness is measured by how well it functions under the pressures of use and occupancy.
Supertalls are seductive, for both the individual and society. Whether 50 or 100 stories above ground, the resident of a supertall occupies a space that no one has ever lived or worked in before – lending an experiential quality to the building type unlike any other. Their presence has also energized entire regions, prompting cities to readily make these billion dollar investments.
In 1996 there were only four supertall buildings in existence. In the decades since, the upward pace of the supertall has been swift and frequent – there are now more than 100 dotted throughout the world – with five of the ten tallest designed by KPF.
For KPF, the quality of a supertall building is a measure of its performance, serving both the society that built it and the generations to come.
In that spirit, KPF focuses on the base of the building as much as its height. One Vanderbilt, a supertall linked directly to one of New York’s most revered landmarks, Grand Central Terminal, is a prime example. Its ground plane was carefully designed to connect to the urban context and improve the pedestrian experience.
The junction of the skyscraper with the ground, with a mix of transport, information, and commercial systems, is one of the most important considerations of all. As with all responsibly designed supertalls, it is the place where the building proves its worth to its city as much as does its presence on the skyline.
Article courtesy of KPF