Technology which will allow an elevator to reach the top of Saudi Arabia’s 1km tall Kingdom Tower in a single leap is being fine-tuned at a research facility in a remote Finnish forest.
An abandoned limestone mine has been developed by elevator company KONE as a secure testing ground for its latest breakthrough in vertical transport.
UltraRope is a high-rise weighted pulley system that will enable lift cars to reach twice the distance previously feasible.
Earlier this year KONE won the contract to provide lifts and escalators for the Kingdom Tower in Jeddah – set to be the world’s tallest buildings when it soars 1,000m high upon completion in 2018.
The building will be equipped with 65 elevators and escalators developed by the Finnish-based company. The design for UltraRope was pioneered at the research facility close to the town of Tytyri, which includes the world’s tallest elevator test tower. This drops to a level 350m below ground and testing is currently continuing in the extreme conditions encountered beneath the surface of the Earth.
“People always ask why go down when you are developing the means to travel to the top of tall buildings,” says Santeri Suoranta, KONE’s director of high rise technology.
“Cost is one reason – this mine shaft was already in place and we just needed to adapt it. We turned the conventional idea of a test tower upside-down. It’s important to develop this technology. As a greater number of people start to live in cities space becomes vital so buildings get higher and elevators become more important.”
The deep mine – part of which is still in operation and producing limestone – also provides an ideal testing environment because of the temperature and climatic conditions it offers.
Suoranta says: “Tytyri is the only test shaft in the world where elevator speeds of up to 17 m/s can be reached, although for us 10 m/s is the usual speed due to the demands pressure changes put on the human body.
“The tough conditions mean we can really push the envelope when it comes to ensuring high safety standards are met and maintained,” he adds.
The technology development takes place amidst an intricate network of shafts, transportation routes and tunnels with the different types of elevator tests including speed, pressure, safety and ride comfort.
The conditions in the mine see temperatures all year measure 6C whatever the ouside to condtions are -30c is not uncommon.
KONE started looking at ways to develop high-rise technology in the late 1990s when the company wanted to establish itself at the forefront of an increasingly competitive field. Its research team developed UltraRope in 2004 with testing then taking place over a nine year period before it was finally unveiled – the level of safety dictated the lengthy time gap.
In tall buildings the height an elevator can reach is limited by the weight of steel ropes needed to hoist it. The rope has to pull up not only the car and the flexible travelling cables that take electricity and communications to it, but also all the rope beneath it.
The job is made easier by counterweights but in a lift 500 metres tall steel ropes account for up to 75% of the moving mass of the machine. Shifting this mass takes energy, so taller lifts are more expensive to run.
Making the ropes longer would risk the steel snapping under the load. But KONE says it is able to reduce the weight of lift ropes by around 90% withUltraRope.
Its engineers say carbon fibres are both stronger and lighter than steel and have great tensile strength, meaning they are hard to break when their ends are pulled. That strength comes from the chemical bonds between carbon atoms – the same process that gives such strength to diamonds.
According to Johannes de Jong, KONE head of technology for large projects, the steel ropes in a 400m-high lift weigh about 18,650kg. An UltraRope for such a lift would weigh 1,170kg.
Besides reducing power consumption, lighter ropes make braking a car easier should something go wrong. Carbon-fibre ropes should also, according to de Jong, cut maintenance bills, because they will last twice as long as steel ones.
The reseach shows that carbon fibre resonates at a different frequency to other building materials, which means it sways less as skyscrapers move in high winds—which is what tall buildings are designed to do. A high wind can cause a steel rope building’s lifts to be shut down. Carbon-fibre ropes would mean that happening less often.
The technology was first unveiled at Marina Bay Sands in Singapore where it allows lifts to reach 200m to the buildings summit.
But its engineers say it will show its full potential when installed in the Kingdom Tower which will have the world’s fastest double-deck elevators with travel speed of over 10 m/s.
“One of the big challenges when you get a building this tall is that if you don’t consider the elevator design carefully, you can end up with a building with a footprint that’s dominated by elevator shafts,” says Aaron Ites, of KONE’s marketing department.
The technology for the lifts and the cars themselves will be constructed at the company’s factory in the Finnish town of Hyvinkaa. Hannu Kikkari, the firm’s global engineering director, oversees the running of the plant. He says: “We have clients who come and see the production process which employs automations and a skilled workforce.”
The technology work has been undertaken in co-operation with the Saudi Arabian client.
”We have been highly impressed with KONE’s innovative solutions to high-rise buildings. This is another cornerstone for a development of this magnitude and we look forward to creating this landmark building in all standards”, says Mounib Hammoud, CEO of developer Jeddah Economic Company.
Noud Veeger, executive vice president for KONE adds: “Close cooperation between all project partners, and with KONE Areeco team locally, our technical professionalism and people flow planning expertise was a winning combination in helping us land the order.”
UltraRope is unique to KONE, although Otis is working on a strengthened steel cable system. Andrew Wood, executive director of the Council for Tall Buildings and Urban Habitat says: “This is finally a breakthrough on one of the ‘holy grail’ limiting factors of tall buildings – that is, the height to which a single elevator could operate before the weight of the steel rope becomes unsupportable over that height.
“So it is not an exaggeration to say that this is revolutionary. However, it is not just the enablement of greater height that is beneficial – the greater energy and material efficiencies are of equal value.”
“This is finally a breakthrough on one of the ‘holy grail’ limiting factors of tall buildings,” comments Antony Wood, Architect and Executive Director, Council for Tall Buildings and Urban Habitat (CTBUH). “So it is not an exaggeration to say that this is revolutionary. However, it is not just the enablement of greater height that is beneficial – the greater energy and material efficiencies are of equal value.”