Dubai Has Built the World’s Biggest Observation Wheel

Located just off the coast of Dubai Marina on the man-made, Bluewater’s Island, Ain Dubai, or the Eye of Dubai is now officially the world’s tallest and largest observation wheel, standing over 250 metres tall and with a capacity of 1,750 passengers at any one time. 82 metres taller than its predecessor, Ain Dubai represents the single greatest increase in height for this type of structure - something that could have only been achieved in a place like Dubai.

So, in terms of structural challenges, I don't think you compare the Ain Dubai with any other wheels, and I probably would say that just because it is by far the largest.

Without getting too technical a lot of the stress relationships are a squared factor, so it's not just a linear proportion, so it gets twice as big the stresses get twice as big. it's a squared relationship and we were pushing the bounds of engineering on this wheel probably more than any other wheel has done before.

Originally set to stand 210 metres tall when it was first proposed back in 2013, the wheel was redesigned and scaled up to a size that would require 33% more steel than was used in the Eiffel Tower.

Now an artificial island, which is essentially compacted sand, might not seem like the best place to build something of this magnitude. But the reclaimed land itself doesn't bear much of the wheel's weight at all.

Drilled to a depth of 35 metres, Ain Dubai’s foundation piles extend five metres into solid bedrock, completely bypassing the reclaimed land - Bluewater’s Island only provides lateral support for the structure.

With a solid base to build on, the hard work began with the four legs, each 126-metres in length, that’s just nine metres shorter than the London Eye’s overall height.

The biggest challenge for engineers didn't come from the leg’s size, but from keeping them standing at a precise angle while the hub and spindle were fitted, they tie everything together and make the structure self-supporting.

There were approximately four weeks 247 welding just to get the legs joined to the spindle. We had the world's third-largest fixed crane capable of lifting 3000 tons. we then bought in the largest mobile crane also capable of lifting 3000 tons the reason. we needed 6000 tons of lifting capacity, it's all about the reach. So you've got to have the ability to lift 1800 tons at a significant distance because you've got the legs in the way and things like that. So that lifting capacity drops quite significantly which is why we needed both cranes to achieve that lift.

While observation wheels look lightweight and simple once complete, getting them to a point where they are self-supporting and won’t buckle under their weight is an extreme structural challenge, and the temporary support structure that makes it happen is like building a whole second wheel within the rim itself.

Once you've got a wheel that's fully built and it's a circle like a bike wheel. It's very strong but the stage before that is you're trying to create that circle that's the challenge. So we started building it up in I refer to it as almost the Dairy Lee cheese boxes, you might be familiar with where you've got the eight triangles that go to make up the circle and realistically. That's exactly how we constructed this wheel and to do that we had what we refer to as a temporary rigid spoke. So that was made out of structural steel rather than cables now the rim itself because they were very slender what we actually had to do is construct and convert the rim into a bridge.

Only when we created a bridge structure could it then span between the two temporary spokes that we'd installed. We were then able um to jack the first segment 100 metres into the air that then allowed us to then lift in the second segment. We then put in another rigid spoke and we would then jack that around.
Now that sounds like a very quick exercise, the reality is that process took three to four weeks to actually go from installing to jacking it, around to being ready to install the next piece.

Once the outer rim was complete, the supporting structure was removed by working backwards - progressively replacing the bulky structural steel elements with 192 pre-tensioned, heavy-duty cables that contain enough wire to reach from Dubai to Cairo. That's 2,400 kilometres if you laid it all out flat, although no one ever does that.

Now we had to be really careful at this point because we couldn't overstress the permanent spokes. So we went around and did a complete revolution of this and again each of those exercises, each of that removing the steel putting in the new spoke cables tensioning up the spoke cables is taking about three weeks. You're almost into six months of work just to remove that steelwork.

With virtually all of the Ain Dubai's structural integrity coming from the temporary framework up. Until this point, every element was painted white to match the colour of the finished wheel. That’s not for aesthetic reasons but to prevent the darker and lighter elements from expanding. Unevenly in the Dubai heat - a phenomenon that could cause the rim to warp and buckle. With its superstructure complete, the
48 passenger cabins were attached to the outside of the rim in a methodical pattern. All to keep the wheel as close to balanced as possible and to prevent its driving mechanism from becoming overstressed.

Now, speaking of the driving mechanism, remember the jacking system that was part of the temporary works? Well, that's now a permanent and integral part of the structure having been modified with 64 types positioned against the rim. They slowly rotate and push the wheel around using friction at a rate of one revolution every 38 minutes.

Designed to carry up to 40 passengers at a time, each cabin is more than double the size and weight of those on the London Eye. Each has been fitted with a
driving mechanism that has the fairly fundamental job of rotating it at the same speed as the wheel but in the opposite direction. So that the floor stays horizontal no matter where it is in the rotation.

If all the passengers decide they wanted to go out to one side um in a Ferris Wheel. But as you might imagine the gondola would all rotate and it would start tipping this experience doesn't happen, because it's all driven and still we have a perfectly horizontal floor for the passengers.

Originally set to open ahead of Expo 2020, like most things last year, that just didn't happen. Ain Dubai is now set to open on October 21st, although press and invited guests will have already been for a ride.

What was my proudest moment there were many just in terms of some of these engineering feats and to have been integrally involved um from the outset on it. However, probably the proudest was I got the opportunity to take some friends and family upon the wheel to be able to share that experience with them and just, yeah, that made me incredibly proud.

While some other great observation wheels have failed to achieve the same popularity as the London Eye, Ain Dubai’s incredible height and unobstructed views will undoubtedly make it the newest landmark in what’s now a city of engineering triumphs.

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