Perhaps I was not complete enough in my answer. The 1.5X rule was what we used in the die business when installing a Socket Head Cap Screw (170 ksi) into a tapped hole in mild steel (60 ksi). This however is irrelevant to the discussion at hand where a 100 ksi fastener is being held in 4 ksi concrete with a 6 ksi epoxy.
That's if they were close to specs and hoping that there is a connection between concrete and epoxy. I would still like to see the actual design that was used. The photograph shows hex head bolts that must be screwed in to something. Did they anchor a female threaded "nut" in the ceiling?
I've used a lot of concrete anchors around the house. I'm going to put a couple in a masonery wall next week. I would never use them to hang something overhead.
The socket head screws you mentioned are generally of a much higher strength material than hex head bolts or stud bolts. That is if you're careful about who made them. So called "certifications" and "quality assurance" documents don't guarantee good bolts.