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Each day, over 7 billion elevator journeys are made in tall buildings throughout the world. It's a staggering fact, but one that goes unnoticed amidst the longer journeys that define urban life. While cars, buses, ships, airplanes, and streetcars, are visible parts of daily life, elevators are housed within individual buildings. And unlike subway rides, which similarly tend to take place below the surface, our vertical trips come as footnotes to the daily commute. Yet, it's those footnotes that make the Toronto skyline—and the modern city itself—possible.
Just as the automobile unleashed the troubled geography of the North American suburbs, the elevator is the keystone to the clusters of skyscrapers that define our ideas of Downtown. If we think of cars when we picture an endlessly repeating grid of houses and lawns, then perhaps we ought think of elevators when we picture Manhattan or Shanghai or the Chicago Loop. The parallels don't end there. Although the basic technologies that make cars and elevators possible have remained largely unchanged for over a century, both are now on the brink of revolution. But while the impacts of driverless cars are fodder for a cottage industry of speculation and analysis, the changes precipitated by multi-cab elevator shafts are quietly poised to transform the urban fabric in their own right.
"The basic technology of the elevator hasn't really changed in 150 years," thyssenkrupp's Ryan Wilson explains. To be sure, advancements in speed, energy efficiency, and safety, have been significant, but the rope, shaft, and cab, is still essentially what it was in the 1850s. Although new computer-operated elevators are faster, more compact, and much more efficient—often feeding energy back into the grid—"the system of ropes and cabins essentially remains the same."
In recent years, faster and more reliable elevators have played a key role in making supertall buildings possible. For supertall projects like the Shanghai Tower and One World Trade Center, or Toronto's own planned YSL Residences, Mirvish + Gehry, and The One, the speed and reliability of elevators is crucial to making the buildings habitable. All the same, as buildings get taller and slimmer, the size of the elevator core comes to occupy a growing proportion of the average floorplate along the way, complicating the viability of added vertical density.
On the supremely thin uppermost floors of the Burj Khalifa, for example, "approximately half of the floorplate is actually the elevator core," Wilson notes, while a look at the 98th level floorpan for Toronto's YSL Residences—the tallest building planned in the city—reveals the scope of the eight-lift elevator core for a floor containing two units (below). In simple terms, the spatial efficiency of elevators—and other elements such as stairs and mechanical spaces—becomes proportionally worse, since supertall buildings tend to thin out towards their peak.
For elevator manufacturers, finding ways to condense the footprint of the elevator core while increasing speed and reliability can have huge impacts. For supertall skyscrapers, a modest reduction of 10 m² per floor yields 1,000 m² over 100 storeys. In extremely high-value urban submarkets like Manhattan—and, increasingly, Downtown Toronto—that 1,000 m² means tens of millions in added revenue, alongside reduced construction costs for the smaller elevator shaft. For developers, modest tweaks to elevator cores and mechanical areas can make or break the economic viability of a project. So what if the average elevator core could be shrunk to less than half of its current size?
For thyssenkrupp, the drive to reduce the footprint of the elevator core has been at the forefront of the company's innovations. Introduced as a concept 2003, thyssenkrupp's 'Twin' system "puts two elevator cabs in the same shaft," Wilson explains. Compared to traditional lifts, the system can carry up to 40% more passengers while occupying 70% of the space, offering a significant—if incremental—improvement over previous technology. Set to be installed in an as-of-yet unspecified high-rise development in Manhattan, the Twin system's commercial introduction will mark a notable step forward for the industry.
In the slightly longer term, however, a much more ambitious technology is being planned, Wilson stresses. Dubbed 'Multi,' a ropeless loop of independently mobile elevator cabs is being touted as the future of vertical transportation. Able to travel both vertically and horizontally, the magnetically charged system can potentially accommodate dozens of cabs. Allowing for flexible and spatially efficient configurations, Multi can "drastically reduce use of space while allowing for new building forms," Wilson notes. Last month, the system was tested for the first time in a custom-built 246-metre concrete tower in Rottweil, Germany, bringing the new technology closer to the market.
Other major elevator manufacturers, such as Otis, Mitsubishi, Hitachi, and KONE, are similarly working to move past the single-cab shaft, though thyssenkrupp's innovations have been the first major advances to be made public. So far, the publicity depicts fantastical towers, characterized by futuristic shapes—made possible by horizontal elevator movement—and staggering heights.
Despite the attention they inevitably garner, however, indulgent megatall buildings like the Burj Khalifa and the Jeddah Tower don't offer any sort of meaningful blueprint for efficient use of urban space. A 700-metre spire will never solve a housing crisis, or radically transform the office market, regardless of revolutionary elevator cores or sky-high property values. New technologies will certainly help make such buildings more widespread, but the more broadly transformative impacts of multi-cab elevator cores are likely to be decidedly less attention-grabbing.
For compact urban sites, the saleable gross floor area (GFA) opened up by a substantially smaller elevator core can make building on smaller lots viable. Here in Toronto, the relatively sprawling podium-and-point-tower sites that characterize much of the 21st century development boom could gradually become a thing of the past as large Downtown sites dwindle, necessitating new typologies.
Allowing tall buildings on smaller footprints, the introduction of multi-cab elevator shafts could spur new types of infill density, while creating the sort of compact, fine-grained frontages that enliven the street far more than a massive retail podium occupied by a Shoppers Drug Mart. For sites that remain too small for a commercially viable tower, a drastically smaller elevator core can make new infill density possible.
For now, of course, the vision of a independent elevator cabs operating in a rope-free system remains the stuff of the future. As the push for urban development intensifies, however, the demand for new technologies will likely make the new technologies a reality. And while the elevators themselves won't be visible in Toronto' skyline, some of the towers that shape the future city will be made possible by the ropeless systems of cabs—and maybe magnets—hidden within.
