When a platoon of soldiers approaches a bridge they " break step " and no longer march as though on parade because a march in unison could resonate with the bridge and cause it to collapse.
12.
Nicknamed " The Trembling Lady " because of its tendency to vibrate when large numbers of people walked over it, the bridge has signs at its entrances that warned troops to break step whilst crossing the bridge.
13.
The Frankie Manning version repeats the basic choreography ( replacing each of the break steps with an 8-beat hold ), then adds two Boogie Back / Boogie Forward phrases and two Boogie Back / Shorty George phrases to the end of the second repetition of the basic choreography.
14.
Concerns about the risks of mechanical resonance effects on suspension bridges, following the 1831 collapse of the Broughton Suspension Bridge and the 1850 collapse of Angers Bridge, led to notices being placed at the entrances warning troops to break step ( i . e . not to march in rhythm ) when crossing the bridge; Although the barracks closed in 2008, the warning signs are still in place.
