Asked by Mark from Gurnee, IL

 

I have a question. I’m reclaiming a dairy barn circa 1945 with foundation re-poured in 1977. It is a common dairy barn within two rows of stanchions and a pad in the middle with a drain trench running through in the shape of a large rectangle.

I can’t seem to copy a photo on to this site but in the concrete are 4 round steel hubs of some sort. They are solid and sunk into the concrete at the corners of the inner pad. They are in the drain trench set just below level of top of trench. They area about 10 inch in diameter and have some type of lid but I cannot find anyway to open them and they are not drains.

There are no drains in the floor or plumbing.
The steel hubs are real solid. I tried to beat them up with a sledge and didn’t even dent them.
Any idea what they could be?