Skyscrapers enable highly (pardon the pun) efficient use of urban space. That urban density doesn’t translate into urban closeness, however, with tall structures acting as roadblocks to mobility. The reason is obvious. When skyscrapers are several hundred metres tall, people sometimes have to cover distances of up to a kilometre simply to get to the same floor of an adjacent building, even if the two are only 50 metres apart. That’s the major disadvantage confronting people in these mobility silos around the world: head down to ground level, walk across, then go back up again. It all takes time and energy.
Architects and city planners are keen to find better ways of connecting the upper floors of adjacent skyscrapers. One of the solutions they’ve devised is the skybridge, which has seen remarkable advances over the last two decades. These spectacular structures redefine the accessibility of high-rise buildings while at the same time creating new, horizontal living spaces at dizzying heights. In the process, they hark back to the age-old vision of cities in the sky. This increasingly popular trend began in 1998, when architect César Antonio Pelli created an observation platform with a pedestrian walkway that joined together what were then the two tallest buildings in the world, the Petronas Towers in Kuala Lumpur. Landmark projects like the Bahrain World Trade Centre have likewise altered our perception of how buildings can be linked. The two main towers of this complex are connected via three skybridges – with attached wind turbines that are visible for miles around. The Council on Tall Buildings and Urban Habitat (CTBUH) recently undertook a study of the role and potential of skybridges and released its findings in 2020.
Many different design options and uses
For the high-rise experts who work with Antony Wood, CEO at the Chicago-headquartered CTBUH, skybridges are structures that are physically connected and supported in their entirety between two or more separate buildings. Under the CTBUH definition, skybridges are located at least six floors above ground level and are enclosed, which means the passageways and spaces housed within the skybridge are under shelter. The principal role of a skybridge is to provide for enclosed circulation of movement between buildings (enclosed circulation skybridge). Occupants of high-rise buildings can use the bridge to move conveniently from one tower to another and reach the upper floors of the adjacent building nearly as easily as they would the higher floors in the tower from which they started. The Highlight Towers in Munich’s Schwabing district (see picture on page 52) offer one example. The elegant, almost transparent bridges that connect the two towers provide a link between the rental spaces in the two office towers. A skybridge on the 20th floor is for the exclusive use of the IBM Watson Centre Munich and adds real value for employees and visitors alike, as Elena Kotlajrova, who heads up Business Development for Facility Management & Real Estate at the site, notes: “The skybridge saves us all lots of time getting back and forth between the towers. Plus, we make conscious use of the skywalk to give our clients an unforgettable experience.”
While according to the CTBUH’s definition skybridges mainly serve to provide a physical connection between at least two buildings, some such structures offer a lot more than that. When additional uses are planned for a skybridge, high-rise experts refer to the resulting structure as an “enclosed programmatic skybridge”. The advantages of this for users are demonstrated in impressive fashion by the skybridge at the American Copper Buildings in New York City (pictured above). The lower deck of this three-level span houses a pool that tenants of the two residential towers can use to swim from one of the skyscrapers to the other. The bridge at the Intempo, Benidorm, Spain, likewise offers upscale benefits.
Here, the 39th to 47th floors of the two approximately 200 metre apartment towers are joined via an eye-catching skybridge. The cone-shaped structure, which accommodates luxury apartments, resembles a gemstone set high between the two residential high-rises (pictured below right). The rooftop terrace on the skybridge is open to all the residents of the twin towers and features jacuzzis, lounge areas and an unparalleled view of the Mediterranean. “The skybridge apartments sell for anywhere between €1.2 and 2.4 million. Of the 30 premium units, nine have already been sold,” comments Janis Fedorovskis, managing director at residential property brokers Engel & Völkers in Benidorm.
Office towers also use programmatic skybridges to make an impression. Nestled behind the red, horizontal stripes of the skybridges at the Tencent Seafront Towers, an office building in Shenzhen, China, are multiple remarkable spaces that even those working in the buildings are probably unaware of (see picture on right). Among the most striking features of the Health Link, named after the programme of the lower bridge on the 21st to 25th floors, are its sports facilities, including a multi-storey climbing wall and a basketball court. This example demonstrates how skybridges open up opportunities for a whole range of mixed-use ideas.
Skybridges offer many potential options for mixed-use concepts
Even an entire skyscraper can be regarded as a skybridge. There are more than a few of this type of skybridge, which unites two separate towers to create a single arched structure and makes for an impressive sight in a big city skyline. In terms of height, they are actually among the world’s highest skyways (see page 50). The skybridge tower at the Address Beach Resort in Dubai takes the lead slot in the rankings of the top 10. Its highest bridged floor is at 295 metres, while the highest skybridge at the Gate to the East in Suzhou, China, lies at 261 metres. There are also skybridges that sit on top of several skyscrapers like an aircraft fuselage. These so-called “skyplanes” form a horizontal tier that extends across the apexes of two or more buildings. The famed Marina Bay Sands in Singapore is one example. This resort offers not only a stunning infinity pool at a height of 191 metres, it also boasts a 340-metre-long roof garden. Among the most spectacular of the recent generation of skybridges is undoubtedly The Crystal in Raffles City in Chongqing, China. The multi-storey, tube-like connector was completed in 2019 and rests atop four 265 metre skyscrapers. Additionally, this skybridge is also linked to the two adjacent 355 metre skyscrapers via another pair of skybridges, making a total of six skyscrapers that are connected 200 metres above the ground.
The Crystal, with its 10,000 square metres of usable floor space, functions much like a city neighbourhood. If the 296-metre-long skybridge were tipped up vertically and placed alongside the Petronas Towers, it would itself be as tall as a skyscraper. Structures as striking as these have thus far been limited to self-contained infrastructures, for practical and legal reasons. As the experts at the CTBUH point out, there’s a lack of regulations on public rights-of-way and shared utility lines, raising serious questions about liability. Cities of the future, however, may well be able to transfer all manner of infrastructures to higher floors. So there’s still huge potential for urban connectivity in the clouds.
By Elke Hildebrandt