Elevators have been around for quite a long time; maybe not those that soar to hundreds of feet in a matter of seconds, but the primitive ancestors of this technology, often man-powered, were developed as early as the 3rd century BC. These early wheel and belt operated platforms provided the lift that would eventually evolve into the “ascending rooms” that allow supertall skyscrapers (above 300 meters) to dominate skylines in cities across the world. Elevators can be given credit for a lot of progress in architecture and urban planning. Their invention and development allowed for the building and inhabiting of the structures we see today.
Supertall skyscrapers are becoming more common as cities and architects race to the top of the skyline, inching their way further up into the atmosphere. These buildings are structural challenges as engineers must develop building technologies that can withstand the forces of high altitudes and tall structures. But what of the practical matter of moving through these buildings? What does it mean for vertical conveyance? How must elevators evolve to accommodate the practical use of these supertall structures?
The early technology of the elevator carried with it many risks. Its counter-weight and pulley systems had no safety mechanisms in case the belts or cables carrying the cars broke. The first safety device was debuted at the New York’s World Fair by Elisha Otis in 1854. He dared patrons to witness as the supporting cable of the elevator was cut, only to find that rather than dropping, a safety device caught the platform, inspiring confidence in elevator design and use. This invention is still in use today and makes elevators much safer, making that 300 meter rise to the top feel a bit more secure. Even with this revolutionary device, elevator technology has evolved in leaps and bounds.
Otis is currently engineering ways to accommodate towers like the Burj Khalifa or the Kingdom Tower, which rise well above the 300 meter mark of supertall and can be called megatall, rising above 600 meters. For the Burj, Otis developed a double-decker elevator, computer coordinated dispatch, and compact lifts, belts, motors and drives that reduce the size of engine rooms. But the main concern is the same safety mechanism and braking system that made Otis such a household name.
What are the considerations for a braking system on an elevator that can go as high as one kilometer? A plummeting elevator car can accelerate to 45 miles per hour and produce as much as 572 degrees Fahrenheit according to Daryl Marvin, director of innovation at Otis. The mechanism that stops this free fall must withstand the heat produced by its acceleration and be able to catch the fall in time. Otis has a test tower that it must retrofit for such speeds in a kilometer tall structure in order to test the various options for this type of scenario.
The developments of these engineered marvels also advance the technology at a much smaller scale. But such supertall structures provide the incentive to develop and test these technologies. As architects dream up taller buildings, engineers in every industry – as has been the case for centuries – will be inspired to accommodate these goals.
via Bloomberg
