How do ocean (or underwater) support beams for a bridge resist corrosion/erosion/rust from water?

Question

I never understood how underwater bridges never collapse. Like they are constantly submerged under water, how do they resist rust? Like ships and other man made objects in the water always het destroyed so how do they do it with bridges?

In: Engineering

Answer 1

A big part of the system are galvanic anodes (https://en.m.wikipedia.org/wiki/Galvanic_anode)

Basically they attach metal that corrodes easier and faster than the structure itself. Protecting the structure and sacrificing the anodes.