Odd 1/2" pipes under slab with "bolts" protruding through end

[MLC]

Installing a bathroom in a walk-out basement in a 95 year old house. While jackhammering the slab around the stack, came across two 1/2"-ish pipes with threaded rod protruding out the ends.

The material almost seems like 1/2" EMT conduit, and based on the damage I've done, don't appear to be sched 40 steel.

The left pipe is securely fastened, perhaps welded, to the top of u-bolts that are well sunk. The other pipe, about 8 inches away, does not appear to be secured.

Any thoughts on what they might be? Photos attached.

Thanks.

 

[FullySprinklered]

Possibly grounding points for lightning rods.

 

[Sponsor]

 

[Dj2]

Wild guess: abandoned pipes.