[bathyspheric]

I don't think the bar would need to be stainless.

The reinforcement cage in concrete weight coating used on subsea pipelines is relatively ordinary steel. The steel is protected from corrosion by the concrete itself and a system of sacrificial anodes that are easy to survey and replace. (I help design pipelines)

[liotier]

> The steel is protected from corrosion by the concrete itself

I guess that the steel is protected by something else because, as the pre-1970 builders ignored and as it dawned on everyone else 20 years ago, concrete is not waterproof.

[dugditches]

was what he was referencing. https://en.wikipedia.org/wiki/Galvanic_anode

[Arizhel]

>concrete is not waterproof.

Ancient Roman concrete is.