Watch: Suspension Bridge Sways Like Crazy-How Safe Is This?
Did you look at the videos? Is this normal? Would you drive across this bridge swaying like this? I didn’t think so. This is a suspension bridge in the Guangdong Province of Taiwan, called the Humen Bridge. Suspension bridges are supported by cables-just like the Golden Gate Bridge in San Francisco. But we don’t ever remember the Golden Gate moving around like this.
That’s what they say. Especially in strong winds as was the case this day on the Humen Bridge. Really? It should be noted that soon after some of these videos were taken the bridge was shut down.
This bridge spans 2.2 miles if you dare
The Humen Bridge spans the Pearl River connecting Guangzhou to Dongguan. Well, it spans it if you’re willing to deal with a twisting, swaying bridge. The length of the span is 2.2 miles.
Officials in Taiwan say the shaking was caused by high winds that hit the bridge which creates a vortex. They went on to say this is normal and that up and down movement within a certain range is safe to drive over. We should note that the bridge was built in 1997.
So, was this movement within a “certain range?” Well, sort of. This is one of the issues with suspension bridges. There are both pros and cons associated with suspension bridges. They’re great at spanning long distances. It can be underspanned when necessary to get some extra length out of it.
The Golden Gate Bridge is only the 12th longest bridge in the world
In spite of the Golden Gate Bridge seeming so long it is only the 12th longest suspension bridge in the world. Japan, China, and Denmark hold the one, two, and three longest.
The other thing about suspension bridges is that they’re cheap to build. That’s supposed to be a positive attribute but that actually seems sketchy for those of us that drive over them. They’re also supposed to be easy to maintain and aesthetically pleasing. Again, not our concern. Our concern has to do with how safe it is.
There are downsides to suspension bridges like this
That brings us to the downside of suspension bridges. Most suspension bridges have a truss system built into them beneath the road to keep it more rigid and less apt to sway and twist. But suspension bridges have to be somewhat flexible during high winds. Otherwise, they may break.
The combined effects of too much weight and wind can lead to breaking support cables. Engineers supposedly take all of this into account when designing the bridge. Not knowing anything about bridges we wonder if that is the case with the Humen Bridge? This is why sometimes you’ll see that vehicles over a certain weight are not allowed to pass on a bridge.
Interestingly, last April the Nansha Bridge was opened to alleviate the heavy traffic the Humen Bridge was experiencing. At least that’s what the Chinese government is saying. It will be interesting to see how long the Humen Bridge will stay in use.