I think every driver experiences that ‘uh-oh’ moment when driving. Whether its a close shave, overtaking a lorry on a motorway in high winds or that grid locked bridge or tunnel causing drivers to feel claustrophobic.
Thankfully, most of the panic it brings is in our head but if your daily commute features a suspension bridge between Nansha District of Guangzhou to Humen Town of Dongguan in the Guangdong province of China – then your fear may very well be justified.
The bridge, that was built back in 1997, measures around 2.25 miles from beginning to end. As you can see from the incident below, the safety of the bridge had been very much compromised and looking extremely dangerous. Thankfully, since the incident on the 5th May, the bridge has been closed until the issue can be rectified.
Now Popular Mechanics have chimed in with their opinion and thankfully given us a more scientific explanation of what is happening here. Mainly, bridges are designed to allow for flexing in the structure, just like skyscrapers can sometimes sway. It’s affectively to allow the structure to be wind tolerant as possible while providing as little wind resistance as possible.
Also discovered was a 1.2 metre tall retaining wall was installed on the bridge’s deck, which effectively created a huge sail. The wind passes over the wall and in doing so creates an air vacuum that actually pull the surface of the bridge up and down.
“Part of the reason suspension bridges are wind tolerant is because they’re “streamlined,” meaning they present as little resistance to the through-flowing wind as possible. When engineers added a new four-foot wall to the suspension portion of the Humen Bridge in Guangdong, China, which opened over 20 years ago, they added what amounts to a wind-capturing sail.”
Thankfully no one was hurt and there are already plans to tear down the offending retaining wall. However, it does make us wonder if anyone will have the confidence to use the bridge again.