burj khalifa

The Burj Khalifa in Dubai is 2,700ft tall

Described as ‘the world’s greatest architect’, Cecil Balmond is deputy chairman of engineering giant Arup. His work includes a new 394ft sculpture for the 2012 Olympics. Here he selects his top ten engineering wonders of the world


1. Millau Viaduct


It took immense audacity to build a cable-stayed road-bridge spanning the valley of the river Tarn, near Millau, southern France. The tallest concrete pylon is 800ft on its own  –  higher than most buildings. On top of that you’ve got the masts, that’s another 280ft, so it’s 1,120ft from the bottom of the valley to the top of the pylons. I like the fact that they built the decking of the bridge in Eiffel’s factories, because I have a soft spot for the Eiffel Tower and what Gustave Eiffel did; he was way ahead of his time. It’s an engineering problem to be slender  –  nothing likes to be slender, it’s not naturally stable. It was a daring design, and it’s a marvel in its own way. All these things take guts and bravery. It’s not just about calculations  –  someone’s taking a huge risk and believing in themselves.

2. Brunelleschi’s Dome


Constructed between 1420-36, the dome of Florence cathedral in Italy spans more than 140ft, but was built with no supporting framework. Architect and engineer Filippo Brunelleschi won the right to complete the dome by saying that he wouldn’t need any internal scaffolding, which was unbelievable in that age. But he invented an entirely new way of sharing the load around the dome so it wouldn’t crack. He also created chains of stone and iron bonded together to make a tension ring, and used a herringbone brick pattern that guaranteed the dome wouldn’t crack. He had to sacrifice part of the theory when he actually built it, which is the sign of a great pragmatist. He believed, intuitively I suspect, that it was enough to spread the load  –  but in the right places. And it worked.

 3. Hagia Sophia 

hagia sophia

The Hagia Sophia in Istanbul, Turkey, changed the history of architecture  –  it changed the way people saw space. It was the largest place of worship for 1,000 years, until Seville Cathedral was built in 1520, and it invented the concept of indirect load transfer. The men who built the Hagia Sophia had the guts to say that the dome doesn’t have to come straight down to the ground. Instead, the dome transfers out in a scallop shape to more domes. That was a massive architectural development, and daring beyond belief. It’s the conception that matters, never the calculation, because they didn’t know all the theories and calculation that we do. Calculation is a red herring in engineering  –  what’s important is an architectural understanding of space.

4. Dutch Delta Works

dutch delta works

In 1953, a major flood killed around 1,800 people in Holland and authorities realised a sea defence had to be built. The answer was to block certain estuaries leading to Antwerp and Rotterdam. The basic premise was very simple: minimise the exposure of the dykes to the sea. But the execution was amazing, and the scale of it enormous  –  the whole coastline had to change. In the Odense area, the sea defence is designed for a one-in-10,000 year surge; in England, the only comparable construction, the Thames Barrier, is designed for a one-in-1,000-year surge. With sea levels expected to keep rising, work to broaden coastal dunes and strengthen sea and river dykes is estimated to continue for another 100 years.

 5. Pyramid of Khufu


The largest of the three pyramids in the Giza Necropolis in Egypt, the Pyramid of Khufu is awesome. For nearly 4,000 years, until Lincoln Cathedral was built in around 1300, it was the world’s tallest building. The impressive part of it is the sheer precision with which the huge blocks of stone were worked. It can’t have been easy, given the instruments at hand in 2700BC, and getting the angles and the alignment correct involved unbelievable precision. The pyramid also adheres to the ‘golden ratio’  –  here in the relative proportion of its height and length  –  which is a notion of aesthetic beauty developed later by the Greeks. I keep expecting not to be overwhelmed by it, because I know it so well, but just walking around it is amazing.

6. Bazalgette’s London sewers

london sweres

Sir Joseph Bazalgette was chief engineer of London’s Metropolitan Board of Works in the 1850s, when sewerage problems led to what was called the Great Stink; cholera was rife. His answer was to build 83 miles of primary sewers, 1,100 miles of street sewers and 13,000 miles of smaller sewers, all underground. He also did one fabulous thing: he decided that whatever calculations he made for the flow of sewage, he would double them, for the future. And had he not done that, by 1950 we would have had the same problem again.

7. Colosseum


This iconic structure, built in Rome between 70 and 82AD, made spectacular use of the arch  –  a Roman architectural invention that has the beauty of opening up space but also being very stable. The Colosseum had four storeys above ground and three below, all composed of arches stacked on top of each other. It had seating for about 50,000 people  –  but could be evacuated within eight minutes. You’d be hard pressed to find a modern arena that could be emptied as fast as that.

8. Channel Tunnel

channel tunnel

The concept of linking two countries was impressive, a fabulous idea. Now, of course, Denmark is linked to Sweden, Macao is being linked to China, but this was the first such project. On top of that was the 67-mile high-speed rail link, running through south London and Kent  –  the Garden of England. The logistics were breathtaking. There are military parallels  –  you plan it so meticulously, otherwise it won’t happen. And it came in on time, which is pretty much unheard of.

9. Panama Canal

panama canal

The genius of the 48-mile Panama Canal (built 1904-14) was not just to link the Atlantic and Pacific, but to raise the canal itself. Surprisingly, the sea level is different on each coast, and there are different levels of high tide. To overcome that, they had to build three locks constructed to a width of 110ft, with lock walls ranging in thickness from 50ft at the base to 10ft at the top. It was designed for 80 million tons of shipping a year, yet today 230 million tons pass along it.

10. Burj Khalifa

burj khalifa dubai

Until recently, high-rise buildings were around 1,500ft tall.

Then came the Burj in Dubai, where somebody just decided to go for broke – it’s 2,700ft tall.

It’s built with something called a buttressed core: you have a strong centre section with legs that buttress it all the way up. When you’re that high, you have to pay a lot of attention to what are known in engineering as secondary effects.

Primary effects include gravity and wind – but at a secondary level, you have to think about temperature and moisture changes, the materials slightly deforming under load.

At this height, anything can be a big problem.

This is where the calculations come into it; they all have to be done quite finely.

I don’t think anyone else is going to go that high – it’s only the money in the Middle East that pushed things so far.

Whether it’s going to be a folly, I don’t know. The Burj is a new way to build and the details are incredible.

The lifts travel at unbelievable speeds: 40mph, whereas normally it’s around 12mph.

Via Daily Mail