When I first saw it I questioned him on it and he assured me it was fine. Over here (in Ireland) anything structural like this needs a certificate of compliance from an engineer. and he should have been engaging with an engineer . So I got in touch with an engineer and he said (based on the photos I supplied) that he was quite worried about the current setup. That it should be like a goalpost. I.e. the RSJ itself is fine but that it needs to be supported by 2 vertical steel beams (on either side) that are cemented into the ground (under the floor).
We were supposed to do something similar basically a RSJ with two steel supports one at each end these were to be resin bonded into a concrete pad, that had to be dug to a certain depth. We had a SE do all the calculations.