I think they're welded to the floor... and I thought the same thing: "That's not good". Heck, I can get steel plate at Home Depot for that; just cut off the bottom welds, slide plate under, bolt to floor then weld cage to plates, right? Should I get a few more tubes for the cage? It looks kind of... sparse, empty, small or weak compared to some others I've seen here.
I got some rebar...
>>Dan