Scantlings

Well, it seems that my physics teachers all had the wrong theory for why the bridge fell down. It turns out it was flutter, the way a mast vibrates back and forth in the wind. Interesting read here:

http://motherboard.vice.com/read/the-myth-of-galloping-gertiea

Thanks for that Beau. Vortex shedding and the first broken cable adding imbalance certainly makes sense. My Dad used to drive across Galloping Gertie and he said when the wind blew it was like being on a boat on the ocean as the cars ahead would disappear when in the "trough". The winds yesterday were 40-45 with higher gusts and toppled an eastbound semi on the newest bridge. I got stuck in the back-up unfortunately.

Here are the Tacoma Narrows bridges yesterday as the winds were winding down. I took this from Titlow Beach just south of the bridges.

I thought they all did that.

The bridge over Eggemoggin Reach to Deer Isle in Maine is very similar to the Tacoma bridge but is still up. After the Tacoma bridge fell efforts were made to keep the Deer Isle bridge stable and they have worked well enough, though the bridge is still closed for severe wind conditions. The bridge has additional stays and as well covering wings on either side of the roadway help stop the bridge from fluttering. You can see the wings easily here-



First lady Rosalyn Carter was forced to stay on the island when the wind came up when she was on the island for some event, IIRC

Tucky wrote:The bridge over Eggemoggin Reach to Deer Isle in Maine is very similar to the Tacoma bridge but is still up. After the Tacoma bridge fell efforts were made to keep the Deer Isle bridge stable and they have worked well enough, though the bridge is still closed for severe wind conditions. The bridge has additional stays and as well covering wings on either side of the roadway help stop the bridge from fluttering. You can see the wings easily here-

Deer_Island_Bridge.jpg

First lady Rosalyn Carter was forced to stay on the island when the wind came up when she was on the island for some event, IIRC

I drove over that bridge and didn't notice the areo kit. Very cool!

Going under that bridge usually mean for me that our cruising season is coming to an end and we're on our way home.