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Mind-Blowing Video Shows How Bridges Over Water Are Built

Mind-Blowing Video Shows How Bridges Over Water Are Built

It's called a cofferdam, and it's a fairly incredible feat of engineering

Tom Wood

Tom Wood

A picture has gone viral showing the incredibly - and seemingly physics-defying - method by which bridges over water are made.

There's also a video that explains the whole thing, which you can watch below:

In the photo, a massively deep hole can be seen in a huge body of water. It seems as if the water should just slosh over the side, but they've got an excavator down in there, showing they're pretty confident.

The structure is something called a cofferdam.

Cofferdams are created when a number of large piles are driven into the water, then the water is pumped out, leaving a lovely and safe environment for people to work.

It's extremely useful when you need to build a bridge across water, but it could also be used to reclaim land if you wanted to build something on there, too.

It would use the same basic principle, anyway.

YouTube/#Mind Warehouse

The technique isn't simply just slamming some walls into the floor, it has to be considered and engineered with great care in order for the structure not to completely flood out or collapse, putting workers' lives at risk.

Without going too far into it, you can't simply slam the structure into the ground, as when water on one side is pumped out, it can cause water to seep up from the ground, thereby causing the structure to be unstable.

So, the piles have to be driven in to a specific depth, which is based on the type of soil at the bottom, as well as observations made on the water table.

Once everything is in place structurally, the water can be pumped out. However, sometimes they also need pumps to constantly remove water that seeps in, should it prove too expensive or difficult to get the piles in to the correct depth.


Of course, it sounds very dangerous, but there are usually a lot of rules in place surrounding the weather.

If those conditions aren't met, people won't be allowed in.

Furthermore, there are protocols to evacuate workers should anything happen, or the conditions become anything less than perfect.

Again, while you might think these would be a relatively new innovation, there is evidence that cofferdams could have been in use since then Persian empire, although they would have been made from earth.

The Romans also made wooden cofferdams when they constructed bridges.

Featured Image Credit: YouTube/#Mind Warehouse

Topics: Science, Interesting, Technology