Fixing a matchbox flyover
SERISH NANISETTI
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Did you know that flyovers are constructed piece by piece?
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CONSTRUCTIVE BRIDGES: A flyover being built in the city
In the dead of the night, as the world sleeps, the blowtorch comes alive as do small metal halide lamps that focus on what's happening in Panjagutta's under-construction flyover in Hyderabad. The men with yellow hard hats work in the night so that the world can move during the daytime, and after a few days, hopefully, faster even during daytime. The huge crane that has been lying idle through the day, comes alive as the operator snags huge pieces of concrete that have been brought from outside the city to fix a "jigsaw puzzle" that has been in the works for the past few months.
The method
Sometimes the pieces are 80-feet spans of cement and concrete that weigh more than 80 tonnes, sometimes there are smaller pieces that weigh under 20 tonnes that have been transported on trailer with dozens of wheels. The crane operator shuffles the gears to get the alignment right and the workers standing on the girders ensure that they don't slip off. Then, as if the 80 tonnes bit was a small matchbox, the crane lifts it and plants it on two steel support structures on two pillars separated by a distance of 80 feet. It leaves one with wonder at the perfection that's being achieved and the sheer scale of the effort. Watching the whole activity brings alive the memories of countless episodes of Discovery Channel about tunnels built under the sea, bridges built in a jiffy and other modern wonders. Of course, most students will remember that the perfection of Egypt's pyramids is such that even a paper will not slide between the two huge blocks of rocks that have been ground so smooth.
The only thing is that the ancient Egyptians didn't have cranes, trailers and computers to do the calculations to the millimetre.
Then how are the pieces fixed so that they don't move and they become permanent structures? Simple. Instead of iron rods, thick iron cables are used to bind the big pieces and the small pieces together.
So, next time you pass by a flyover, see the mathematical and technical wizardry at work.
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