Martin Antonenko
A Fixture
- Joined
- Jul 11, 2008
- Messages
- 8,794
Marching in Lockstep Kills...!
In September 1838, the old stone bridge over the Maine River was in the French city of Angers in the Maine-et-Loire Département ...
... has been replaced by a Catenary suspension bridge of the latest design ...:
Due to its great height, it should facilitate shipping traffic on the river.
In the next "aerial photo" it can be seen as the front bridge...
The main users are the soldiers of the 6e régiment du genie (6th pioneer regiment) from the nearby barracks in the fortress, who march almost daily over the bridge to the firing and training areas.
Since the collapse of the similarly constructed Broughton Suspension Bridge near Manchester ...
... in England in 1831 it is common knowledge that bridges can be caused to vibrate and ultimately collapse by the lockstep of a column of soldiers (79 dead) ...
... there is the strict order to cross the bridge in Angers "without step" (not in lockstep!) and without singing (because singing leads to unconscious marching in time and thus to "step in step")!
This will go well for twelve years!
On the morning of April 16, 1850, three battalions marched one after the other across the bridge on the way to the firing range.
On this day it is quite windy and the gusts of wind make the bridge vibrate slightly.
The first two battalions cross the bridge in the ordered "disorder" with no problems.
The 720 soldiers of the third battalion follow. When the head of the column is in the middle of the bridge, a heavy cold rain shower comes down on the soldiers! Even though they march "without a step", the rear part of the column pushes faster to get out of the rain - the vibrations of the bridge increase!
And the soldiers unintentionally adapt their movements to the situation and "brace" themselves against the vibrations with their steps.
The result is: An actually unintentional similar movement of the 720 people - a kind of "lockstep".
Now happens what has always been feared:
Suddenly the ropes on the right bank tear, the two pylons fall from their bases and the roadway falls diagonally into the river on the right, while it is still held on the other side by the ropes and the intact pylons.
The entire battalion plunged into cold water.
226 soldiers perish - the collapse of the Angers Bridge is one of the worst bridge accidents in history.
The fatal resonance effect that the unintentional lock step of the soldiers had on the stability of the bridge was - as it comes out later - intensified by botched construction:
The steel suspension ropes were only incompletely protected against corrosion with lime paste, they had now rusted considerably and their load-bearing capacity was greatly reduced ...
When rebuilding the bridge, play it safe and build a stone structure again. That is still there today ...:
In September 1838, the old stone bridge over the Maine River was in the French city of Angers in the Maine-et-Loire Département ...
... has been replaced by a Catenary suspension bridge of the latest design ...:
Due to its great height, it should facilitate shipping traffic on the river.
In the next "aerial photo" it can be seen as the front bridge...
The main users are the soldiers of the 6e régiment du genie (6th pioneer regiment) from the nearby barracks in the fortress, who march almost daily over the bridge to the firing and training areas.
Since the collapse of the similarly constructed Broughton Suspension Bridge near Manchester ...
... in England in 1831 it is common knowledge that bridges can be caused to vibrate and ultimately collapse by the lockstep of a column of soldiers (79 dead) ...
... there is the strict order to cross the bridge in Angers "without step" (not in lockstep!) and without singing (because singing leads to unconscious marching in time and thus to "step in step")!
This will go well for twelve years!
On the morning of April 16, 1850, three battalions marched one after the other across the bridge on the way to the firing range.
On this day it is quite windy and the gusts of wind make the bridge vibrate slightly.
The first two battalions cross the bridge in the ordered "disorder" with no problems.
The 720 soldiers of the third battalion follow. When the head of the column is in the middle of the bridge, a heavy cold rain shower comes down on the soldiers! Even though they march "without a step", the rear part of the column pushes faster to get out of the rain - the vibrations of the bridge increase!
And the soldiers unintentionally adapt their movements to the situation and "brace" themselves against the vibrations with their steps.
The result is: An actually unintentional similar movement of the 720 people - a kind of "lockstep".
Now happens what has always been feared:
Suddenly the ropes on the right bank tear, the two pylons fall from their bases and the roadway falls diagonally into the river on the right, while it is still held on the other side by the ropes and the intact pylons.
The entire battalion plunged into cold water.
226 soldiers perish - the collapse of the Angers Bridge is one of the worst bridge accidents in history.
The fatal resonance effect that the unintentional lock step of the soldiers had on the stability of the bridge was - as it comes out later - intensified by botched construction:
The steel suspension ropes were only incompletely protected against corrosion with lime paste, they had now rusted considerably and their load-bearing capacity was greatly reduced ...
When rebuilding the bridge, play it safe and build a stone structure again. That is still there today ...:
