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It looks similar to the description of the bridge being built in "World without End" by Ken Follett. One bit that is missing from this animation is that there i

It looks similar to the description of the bridge being built in "World without End" by Ken Follett. One bit that is missing from this animation is that there is no rubble placed in the water around the piers. In the book this had the all important function of preventing the foundations from being washed out by the river. Maybe that was fiction or it was too much detail for the animators since the water is not transparent.

SideburnsOfDoom 6y ago
I expected there to be some kind of "foundations"? i.e. once the water is out of the enclosure, you have a surface that is likely to be soft wet mud or sand. Surely you want to scoop some out, dig down and lay some big blocks of stone under the river bed level? Or maybe that happens, but was just not shown. Or maybe, once you start building up, the sheer weight pushes the whole column down until it settles.
- evgen 6y ago
  Dig to bedrock or drive in pilings to shore up your foundation if you can, it all depends on the local geography. Given the lateral forces on a bridge it seems unlikely that modern builders would float the footings of the arches in the riverbed, but in the case of this bridge I think that was what happened (a guess given the fact that three arches failed during a flood in 1890s when a pile-up of logs and debris forced a lot of water flow to push deeper to pass the bridge.)
- prennert 6y ago
  In the book the issue was that the sand around, and eventually under, the foundations washed out over time so the piers started to be effectively suspended from the bridge rather than supporting it. Rubble around the actual foundations were needed to defuse the drag of the water around the foundations, preventing the washout.
rimliu 6y ago
https://en.wikipedia.org/wiki/Charles_Bridge https://en.wikipedia.org/wiki/Charles_Bridge
- prennert 6y ago
  Oh wow. > In 1496 the third arch (counting from the Old Town side) broke down after one of the pillars lowered, being undermined by the water (repairs were finished in 1503). So that suggests there were no, or too little, defences against washout of the foundations originally.
  - JoeAltmaier 6y ago
    Or, no divers inspecting the pillars and foundations against erosion. It was easy to get complacent in the old days, after the Engineer died, and just assume the old monuments were eternal.
PoignardAzur 6y ago
Yeah, my first thought when seeing the cofferdam was "hey, I know what these things are!"

SideburnsOfDoom 6y ago

I expected there to be some kind of "foundations"? i.e. once the water is out of the enclosure, you have a surface that is likely to be soft wet mud or sand. Surely you want to scoop some out, dig down and lay some big blocks of stone under the river bed level? Or maybe that happens, but was just not shown. Or maybe, once you start building up, the sheer weight pushes the whole column down until it settles.

evgen 6y ago
Dig to bedrock or drive in pilings to shore up your foundation if you can, it all depends on the local geography. Given the lateral forces on a bridge it seems unlikely that modern builders would float the footings of the arches in the riverbed, but in the case of this bridge I think that was what happened (a guess given the fact that three arches failed during a flood in 1890s when a pile-up of logs and debris forced a lot of water flow to push deeper to pass the bridge.)
prennert 6y ago
In the book the issue was that the sand around, and eventually under, the foundations washed out over time so the piers started to be effectively suspended from the bridge rather than supporting it. Rubble around the actual foundations were needed to defuse the drag of the water around the foundations, preventing the washout.

rimliu 6y ago

https://en.wikipedia.org/wiki/Charles_Bridge https://en.wikipedia.org/wiki/Charles_Bridge

prennert 6y ago
Oh wow. > In 1496 the third arch (counting from the Old Town side) broke down after one of the pillars lowered, being undermined by the water (repairs were finished in 1503). So that suggests there were no, or too little, defences against washout of the foundations originally.
- JoeAltmaier 6y ago
  Or, no divers inspecting the pillars and foundations against erosion. It was easy to get complacent in the old days, after the Engineer died, and just assume the old monuments were eternal.

PoignardAzur 6y ago

Yeah, my first thought when seeing the cofferdam was "hey, I know what these things are!"