Quote Originally Posted by bruce.desertrat View Post
Interesting frequency harmonics there...only the middle tower is swaying. modern skyscrapers have extensive damper structures to prevent swaying in the wind and in earthquakes. The frequency of the earth movement must have synched with the height of that particular tower, and not with the other two.
That's interesting and a massive oversight on the part of the engineers. Why on earth wouldn't you tune each structure to have the same natural frequency if you're going to connect them with a bridge?