When I poured my floor, I looked at several options for tie downs.  One that I considered, but didn't install, was pipe-like openings with a cross bar, a plate on the bottom.  One could hook a chain in the crossbar, and they had covers to help keep them clean when not being used.  Always figured I would regret not installing them, but never did need them.  Good idea, something out of the way that could be used to straighten something.  I usually hooked onto a large tractor or combine, which worked with anything I wanted to do in the shop.