Our facility has a pavilion made of steel beams. Most of the columns are anchored in concrete. However, there are three columns that are anchored inside a raised garden. As a result, they are in constant contact with the soil, which is causing corrosion. The problem is not too dire, at the moment. However, in time, this could become a serious problem for the stability of the structure.
The challenge is how to protect the steel columns. Any repairs that we make buy grinding down the rust and painting the columns would be temporary and have to be repeated until the columns have to be replaced completely.
A couple of solutions come to mind. One, I can tear down the raised garden around the columns and leave them free-standing so that the soil no longer corrodes the iron. This would require the expense of labor and materials. And, once complete, we may find that the column no longer has visual appeal from the rust scars.
Another solution is to attempt to attach a sacrificial anode, which would be buried next to the column. This would slow down the corrosion as the majority of the activity would take place on the anode rather than the steel column.
My research has yielded some useful information about sacrificial anodes. Most are made of Magnesium, Aluminum, and Zinc. Of those, Aluminum and Zinc anodes are principally used in salt water. Magnesium is used in fresh water or buried pipelines.
I could not, however, find any information on anodes made for the purpose of preserving structural steel. The only anodes I could find are Magnesium discs for boats and rods for water heaters. I may have to fashion some sort of remedy out of components. To me, it would be a simple matter to fasten an insulated lead to the bare metal of the column and to the sacrificial anode. However, as in most things, I suspect there is a science to corrosion.
I may need to consult an engineer to figure out a simple solution to the problem. While we are at it, we could figure out a maintenance schedule to replace the sacrificial anodes.