If the walls were poured separately from the floor (you can tell if there is a seam around the edge of the floor) then you must consider them as two completely separate structures. Even if there was rebar stubbed to carry through to the next pour, they do not have structural integration.
I've told this before, but a fellow I know took a 1940's Craftsman (Atlas-built) 12" lathe and formed up two pyramids to cast concrete tied into a concrete floor. The pour for the pyramids was carried up high enough the capture the feet of the lathe bed, with long anchor bolts using the existing mount holes in the feet. This set-up was used to make 1" Acme double lead screws for a paving machine. The spindle was modified to a roller chain drive, and the threads were cut in three passes. The pyramids were like adding 1,000 pounds to the weight of the machine, in terms of rigidity.