Glass Bridges: the New Thrill Ride?

July 18, 2016 | Comments

A group of giggling schoolgirls put away their smart phones to pick up sledgehammers so they could take whacks at a glass bridge they were standing on. They laughed nervously as cracks formed under their feet. Were they candidates for the Darwin Awards? Participants in a sorority stunt? Rich kids out to vandalize public areas just for kicks? None of the above.

This was an event staged by Chinese government engineers to prove that their glass bridge is not as fragile as it sounds. Apparently, the Xhangjiagje Grand Canyon Bridge, located in China’s Hunan province, can sustain quite a bit of damage without everyone on the bridge plunging down a 300-m chasm.

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Shouldn’t someone stop this girl? Chinese officials staged a demo of the toughness of “longest, tallest glass bridge.” (Image courtesy of New China TV.)

The glass did crack with repeated blows,but since there were three layers of glass panels in the bridge deck, everything stayed in place. A spiderweb of cracks on top only meant that the top panel had to be replaced. The deck would still not fail even if two layers were damaged, according to the bridge’s engineers.

The engineers spoke with some certainty. Before they imperiled schoolgirls, construction workers in safety harnesses had been whacking away at the bridge with sledgehammers, too. Then, for good measure, they drove an SUV over the crunching broken glass.

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The Zhangjiajie Grand Canyon Glass Bridge stretches across a 1,200-foot canyon. (Image courtesy of Haim Dotan Ltd.)

This glass bridge was designed by an Israeli engineer, HiamDotan. Glass, never the first choice for bridge decks, is nevertheless becoming a thing.

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Tourists stroll on the SkyWalk, 4000 ft above the bottom of the Grand Canyon. (Image courtesy of the Grand Canyon National Park.)

Perhaps the most famous glass bridge in the U.S. is the SkyWalk over the Grand Canyon. China appears to want to be the world leader in glass bridges, with several already in existence. A glass walkway on the sheer side of the 3450-foot-high Yuntai Mountain in China caused a panic after it developed a crack, probably from a falling rock. Only the top panel was damaged, however, and the bridge was in no danger of collapse, according to officials. The same officials may have decided schoolgirls with sledgehammers would forestall future panics.

It is the perceived risk of danger that makes structures like this into tourist attractions. Chicago’s Willis Tower developed cracks in its protective coating, causing a panic among the tourists on location. The public was assured that because of the integrity of the three-layer glass construction, the bridge was never compromised. London’s Tower Bridge installed a glass panel, which later cracked from a falling beer bottle. The bridge and beer drinker both appear to have survived intact.

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Why do we fear resting on glass? Glass-bottom walkways like this one from Jurassic Park: The Lost World show a thrilling (if not realistic) example.(Image courtesy of Universal Studios.)

Glass, never the structural material, has found its place as a tourist attraction, now providing a thrill to those in high places who found walking on concrete and steel boring.

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