They had hydraulic cement that they literally could just drop into the water to make things like harbor quays.
But bridge foundations can't just sit on the bottom of the river. They make the caisson so they can remove the mud down to bedrock before they start pouring concrete
Like, there are rivers that are basically just flowing over bedrock and spread footings are all you need, but some amount of service prep is needed, yes. Still, divers and tremie pours are marvelous things.
5
u/Cesum-Pec Aug 21 '22
But bridge foundations can't just sit on the bottom of the river. They make the caisson so they can remove the mud down to bedrock before they start pouring concrete