Because the wind blows with bridge Frequency is equal to the natural frequency of oscillation of the bridge swing bridge, making it harder to break down in the end.
The wind blew and struck the bridge. A frequency equal to the natural frequency of vibration of the bridge. Making it harder swing bridge I finally broke down.
Because the winds affect the bridge. The frequency of the natural frequency of vibration of the bridge. The swing bridge strength up until the fall in the end. .