Modern elevator technology cuts through high rise rules

Elevators are a crucial element of any high-rise building, but until recently they imposed serious constraints on the overall height of the building.

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By  Colin Foreman Published  July 13, 2004

Modern elevator technology cuts through high rise rules|~|Gary body.jpg|~||~|Elevators are a crucial element of any high-rise building, but until recently they imposed serious constraints on the overall height of the building. Limited core space and acceleration rates meant that it was not practical for a building with much more than 100 storeys. Recent changes in the elevator industry and technological advances mean that buildings are now free from these constraints allowing for a new generation of super tall buildings. Construction Week spoke to Gary Elliott, global chief executive officer, Thyssenkrupp Elevator about how the industry has changed, how technology has advanced and why record-breaking projects like the Burj Dubai are now possible.

When did you begin working in the elevator industry?

I started work in this industry at the end of the 1960s. Back then virtually every country had its own factory for manufacturing elevators so it was a very diverse market. Over the last few years the industry has become much more concentrated so the smaller companies can no longer compete because of the operational efficiencies that the larger players have gained over the years.

What is the most important market globally for elevators?

Europe has always been the most important low-rise market. The difference between the European market and the North American market is that the majority of people in North America live in low- or single- storey houses as opposed tower blocks like many do in Europe. When you look at cities like Moscow that developed many high rise apartment buildings during the communist times, it has 120 000 elevators alone, even though they are not very technical or high quality.

What about new installations?

On the new installation side of things Asia has now past Europe. There are 250 000 new pieces installed each year worldwide. About 110 000 of these are in Asia, with 60 000 going to its biggest market China, followed by Japan and Korea and the rest. Europe installs 90 000 pieces a year with about 50 000 pieces going to the rest of the world.

How significant is the Middle East?

Today it is relatively small, but it has lots of potential.

How important is the Dubai market?

Dubai is an important market for several reasons. It has this will to develop in a hurry that is perhaps the strongest in the world today, with the possible exception of China. There is a will to make the city a recreational centre, a business centre, and a health centre to attract people from around the world, and an important part of our business is to service those industries.

What products types do envisage the city will need?

The city will need elevators, escalators, and boarding bridges. Escalators have three main clients: Shopping centres and department stores, airports, and subway systems. Airports clearly have a big potential here with the airport expansion here in Dubai the new airport being built in Qatar.

How much of a role has product development played over recent years?

It has played an enormous role. Over the last ten years the elevator industry has evolved from a relatively conservative industry with a few market leaders using older technology into a high tech industry. Just one example of technological development for elevators is electronics. Although the electronics industry went from relay technology, to solid-state technology and then to micro technology, most of the elevator industry jumped from relay technology to micro technology and missed that middle step. Electronics now plays a large role in product development. Electronics are used to perform safety functions that were previously performed mechanically. Advances have also been made on the mechanical side as motor control has developed enormously over the last 10 to 15 years.

How much of a shackle has elevator technology been on building heights?

Complete. It’s not only about core spaces and maximising rentable space, it’s also about acceleration rates. The rule of thumb is that no one should be in an elevator for more that 60 s. That means the express run from the lowest floor to the highest floor of a building shouldn’t be more than 60 s. So acceleration and deceleration has been a restricting factor because you can’t ramp up too quickly because passengers will become nauseas.

Will the 60 s rule apply to the Burj Dubai?

I haven’t looked at the study but I am sure it will be.
Does cable weight become a problem in super-tall buildings?
Once a building exceeds 15 floors the weight of the cables is compensated by hanging cables under the elevator. What is more important for high-speed elevators is the wind dynamics because you can’t have people popping their ears in the cabin. The wind noise in an elevator shaft is huge and it has to be dampened using aerodynamics and pressurisation on the doors and the shafts to stabilise the pressure. Wind will always wants to go up so it can create massive updrafts if it is not pressurised properly. This requires a huge amount of work when designing an high-speed elevator system for super-tall buildings.

Are there any other design issues for super-tall buildings?

High-speed safety devices are crucial. The classic example is when all the elevator ropes fail at the same time and the system must prevent the cabin from freefalling. Traditionally this was done using steel plates that bite onto the tracks of the elevator bringing it to rest. At such high speeds the steel will melt so specially developed alloys have to be used.
Electronics also play an important role as the final safety device. The system is operated by a speed governor that runs through a cable up the whole length of the shaft. Thyssenkrupp Elevator has just won a contract on the rebuild of the Moscow Tower and the company is supplying a big electrical cable with the cabin, called a travelling cable because it runs with the car. Cableless Blue Tooth technology is also being used on that project and will also play a big role in the Burj Dubai.

Will the Burj Dubai have a destination control system?

I don’t think the Burj Dubai will have destination control, but it should. There are efficiencies that can be generated by destination control. If the system doesn’t know how many people want to go to each floor, and traditionally this was not known till the people entered the car and then its only an approximate guide because they are weighed so the system still doesn’t really know how many people want to go to each floor. With destination control the system knows where everybody wants to go so it can send the most appropriate car.

There was some talk of the Burj Dubai having triple-deck elevators.

The Burj Dubai is a very unique project in that it will require the fortunate elevator contractor to prove its technical abilities. Double cabin will most likely not be a part of that solution because the building steps down so far that there are only two elevators that can go 18 m/s.

When is the contract going to be awarded?

My guess would be that the contracts for the project won't be awarded until the end of the calendar year. It is very important for us to show our technical capabilities.

Is it a little unusual for the elevators to be procured so late in the project?

Not necessarily. The elevators and escalators are normally awarded early in the project because we are one of the last finishing trades and the building can't open before the elevators are running so it is important to award the elevators early. The project managers know how long the installation will take so they will ensure there is enough time for the installation process, and its up to them when the elevators contracts are awarded.

Can you explain what the Twin system is?

Twin is a very exciting new product range that has just been introduced to the market. Basically there are two drive machines at the top of the shaft, either on top of one another or beside each other with separate cables going to each cabin and a very complex control system to ensure the two cabins don't run into each other. Instead of traditional push buttons in the lobby there is a computer screen for passengers to tell the system where they want to go. The system then informs the passenger which cabin to take. There are no buttons in the cabin so it is very elegant looking, and it automatically takes you to your floor. This facilitates higher rise buildings and saves space for the developers.

Has the Twin system been installed anywhere yet?

Twin’s first installation was a prototype installation at the University of Stuttgart, which is only a 10-storey building, but the original building was only planned for 800 students and then later, because the classes became larger it had 1400 students in the same building. The result was that there were long queues for the elevators so we decided to see if Twin would help. After the system was installed there we no more line ups as the same number of students could be managed with the same number of shafts, but with more cabins.

Any other innovative products been developed recently?

One other revolutionary product is Isis where instead of using steel cables, aramid fibre cables are used. These cables are much stronger than steel and have a much shorter bending distance that allows the smaller machine to be smaller so that they can be housed in the elevator shaft itself instead of taking up valuable space in a machine room. Another revolutionary product that will be extremely important for airport technology will be for the long walkways that from the aeroplane through the terminal, that are relatively slow moving sidewalks where you have to move on one walkway and get onto the next one.
This product is an accelerating moving walkway so you get on at one speed and it accelerate to three times the speed over the long distance covered, and decelerated to let people off at the end of the walkway. We currently have a prototype of this product running in a factory in Spain, but it only has a length of 80 m, the product could cover distances of about 1 km so it could encroach on the automatic people moving market like those the cabins found in some airports.

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