Bridges are considered symbols of peace. Maybe that’s a little bit because even entire marching battalions suddenly seem much more peaceful on them. Because they are not allowed to move in step there.
As far as is known, the first official order in this direction was issued after a chain bridge collapsed near Manchester on April 12, 1831, 192 years ago today. Soldiers of His Majesty the uncrowned new King William IV, who incidentally recently lost the record as the oldest heir to the British throne when he took office, were walking in lockstep across the Broughton Suspension Bridge over the River Irwell towards the barracks.
Its frequency, as we now know, was close to the resonance frequency of the bridge. The vibrations could be seen, felt, and were further amplified by the rhythmic impact of the soldiers’ feet. A design flaw in the bridge contributed to the fact that it ultimately could no longer withstand these forces and collapsed.
A song
Numerous soldiers were injured, but according to historical documents none died.
As far as is known, the approximately 70 men did not initially walk in step anyway. In a relaxed mood towards the end of the day, they had apparently only fallen into him because of a song they had started.
Such resonance phenomena often occur spontaneously and can become problematic. For example, the “Millennium Bridge” in London began vibrating visibly in June 200, just on the day it opened.
disaster in India
“Many pedestrians spontaneously fell into the vibrations of the bridge and unintentionally amplified them,” says a 2005 publication in “Nature”. analysis. According to official statements, there was never any danger. But the bridge was closed for a year to install dampers to prevent just such events.
The last event in which, according to eyewitnesses, people on a bridge increased their own vibration and this possibly contributed to the catastrophe was less than a year ago. Here, too, many people were involved in a newly opened, although in this case renovated, such building. At least 135 people died when the bridge over the Machchhu River collapsed in Morbi, in the Indian state of Gujarat.
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