They’re basically foundation bolts right? Pick them up at any building supply.
No they aren't. I make them from 1/2" X 13 thread bolts. Cut off the heads, heat with acetylene torch, bend 90°, cut the thread end to the right length for clearance and chamfer. I found no similar bolts, looked for them & found I had to create them. At first I welded them but found the hard way hot-forged are stronger. Now if such a bolt exists with the right dimensions and strength I would be all over buying them instead.
I'm finding similar shaped bolts now. Might be I can find and order them instead. Hope so. I'm just now making another batch; no doubt it would be cheaper to buy them pre-made, rather than buying conventional bolts and spending the labor and gas to modify them.