As I confessed, this was the first time I had to deal with this sort of structure. Where I come from, most everything is brick!

For the repair, I will be using toggle bolts. I would prefer the nut / fender washer arrangement, but the 'back side' of the metal is not accessible.

Around here, the ground is rather corrosive to steel. Moreover, this "open" lot is not anywhere near flat, and is now filled with dozens of cars. Part of me suspects that someone stood on the pipe to work on the cars- or worse.