Designing ultra-efficient elevators to go faster and higher is only one of several challenges facing the builders of ever taller towers. As they reach for the sky, other obstacles include:
Turbulence increases at higher altitudes, exerting huge pressure on buildings. Super-tall towers already sway to compensate. But they can only move slightly before people inside the building start to feel the movement. Engineers are constantly working to reduce wind resistance. Water tanks also help dampen movement.
Moving water and sewage around super-tall towers creates a variety of challenges. Behind the sheer volume of pipes, nobody wants to hear water rushing through the building. Designs typically include curves and various holding tanks to slow the flow.
Most of the super-tall buildings in the Gulf are built with cement. But getting cement to great heights quickly and efficiently is not easy. Among other records, Dubai's Burj Khalifa, the tallest building in the world, set a new standard for pumping cement to altitude.
Tall buildings require kilometres of complicated wiring. The length of the systems is not necessarily a problem, but the bulk becomes a critical issue. Space must be found to run the wires and pipes and that takes away from usable space, which is at a premium in super-tall towers.
The 9/11 attacks on the World Trade Center towers provided vivid evidence of the horrors involved in trying to emergency evacuate very tall buildings. The tragedy brought safety to the forefront and helped to spur a rethink of strategies. Typically people are told to avoid lifts in an emergency. But new systems call for elevators to bring people to safe areas on different floors and to additional escape routes.
Buildings grow more expensive as they rise. But developers have compensated by building larger projects on the ground floors and charging more for land and projects around super-tall towers.
* Kevin Brass