Estonian ice road and resonance wave destruction - video and photo

[Jon]

Ice road in Estonia (pretty much what it sounds like: Ice road).



The road is open from 10am until 5pm, and is limited to vehicles under 2.5 tons. Drivers are forbidden from wearing seatbelts (assumedly because of the need to rapidly exit a sinking vehicle).

Most interesting - there is a dual speed limit in place: roughly under 16mph OR 25-43mph. This is to prevent creating a resonance wave in the ice layer which could break the ice.

I think they're trying to avoid something similar to the famous Tacoma Narrows bridge collapse:

Previously:

Ice sled propelled by saw blade
The Tyrolean Iceman's tools - photos and images

[neilbourjaily]

45 years ago we regularly went nighttime skiing on our wooden XC skis. Finally it was cold enough for Columbine lake at app 9000 ft in southern Colorado to have frozen. Across the lake we skied. Suddenly, the surface began to pitch and roll. "Break stride," cried out Captain Larry. Had we not 8 of us would have gone through the ice. Later while relaxing with our intoxicants of choice, Larry told us how troops always break stride when crossing a bridge. It is this same pnemonon that leads to washboards in our dirt roads. Thank you Captain Larry.

[Nick79]

The “narrows” was shown every year to my students when I was teaching Physics. I used it to get their attention for the lessons that followed. It helped every time. An engineering disaster but an excellent teaching moment.