The dreams of engineers

Humans like to build impressive things–witness the Pyramids. Today’s technology is making possible feats of engineering that would have seemed like science fiction just a few years ago.

In the current issue of Popular Science, Carl Hoffman provides a round-up of upcoming engineering marvels. I’m just going to mention a few.

One sure path to engineering glory is to build the world’s tallest building. Currently the record-holder is in Taipei, but soon it may be in Dubai, business capital of the oil-rich United Arab Emirates.

Although its exact height and number of stories are being kept secret by its developers, early designs show the Burj Dubai, a combination residential and hotel tower, coming in at well over 600 metres–more than twice as high as the Empire State Building. To damp out the vibrations caused by 190-kilometre-an-hour winds swirling around the building’s pinnacle, it will be made of poured concrete mixed with blast furnace slag and microsilicates, a material almost as strong as cast iron but more resistant to vibration, and will numerous setbacks and wings, creating 18 different sections, each of which disrupts the wind differently.

The top of the Burj Dubai should give visitors a great view of another engineering marvel, the Palm and World Islands. The Palm Islands are two artificial islands, 4.8 kilometres offshore, being built in the shape of giant palm trees, with “trunks” eight kilometers long and topped with 17 “fronds” up to 100 metres long. One has already been built; the second is underway. The World Islands will be an archipelago of 250 artificial islands, eight kilometers across, laid out to mimic Earth’s land masses.

Another way to earn engineering bragging rights is to build a really big bridge. If the money can be found, Italy wants to build the world’s largest suspension bridge across the Strait of Messina dividing Italy and Sicily. It would consist of a single 3.2-kilometre-long, 10-lane span suspended from 1.2-metre-diameter cables strung from 300-metre-tall towers built on the mainland and the island. Since the towers would be located on land, the swirling currents of the strait wouldn’t be a problem; the suspension design would also allow the bridge to flex up to almost 10 metres during an earthquake (there are 100 active seismic faults in the area). Wind could threaten both the bridge and vehicles on it, so engineers have designed steel box bridge sections to deflect the air.

Today, England and France are connected by a tunnel under the English Channel. Someday, North America and Europe could be connected by a tunnel under–or, rather, through–the Atlantic Ocean.

Engineers Ernst Frankel and Frank Davidson, both formerly of MIT, envision a neutrally buoyant tube submerged 50 to 100 metres beneath the Atlantic’s surface and anchored to the seafloor. The air would be pumped out of the tube, creating a vacuum, allowing alternating magnetic pulses in the wall of the tube to speed a magnetically levitated train across the Atlantic at 6,400 kilometres per hour–fast enough to make the trip from New York to London in an hour.

Even if you’re never able to take a train across the Atlantic, you might be able to take an elevator into space. The concept of a space elevator–a 100,000-kilometre-long cable with one end “anchored” to an orbiting platform and the other attached to the Earth somewhere on the equator–has been around for many years. Now we finally have a material light enough and strong enough to build it. Carbon nanotubes, tiny tubes of carbon atoms that are 60 times stronger than steel, can be combined with an epoxy resin and extruded like fishing line. Brad Edwards, director of research at the Institute for Scientific Research in Fairmont, West Virginia, has done the calculations and concluded there are no physical reasons why a space elevator couldn’t be built using this material.

In his plan, a rocket would launch an anchor satellite to geosynchronous orbit (100,000 kilometres out), where it always stays above the same place on the Earth. A ribbon made from carbon-nanotube composite fiber would be unfurled the entire distance. Automated “climbers” would strengthen the initial ribbon with additional layers of carbon-nanotube fiber, creating a cable a metre in diameter. Technicians would attach it to a platform floating in the Pacific Ocean at the equator.

Electric elevators, powered by an infrared laser beaming energy from the ground, could then simply climb up and down the cable, carrying as much as five tons of payload into space at a time, cheaply and safely.

Faster, higher, stronger–the motto of the Olympics, it seems, is also the dream of engineers.

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