I have a case where the anchor rods have been set too low (again). They are F1554-36 1 1/4" diameter. To make things worse, the columns have fixed bases and have been installed with the grout below the base plate installed. I'm not sure why the contractor even bothered to call this in this late.
Typically, if the rod head is flush with the top of the nut, we use the full strength of the rod. Is there a way to determine what the connection strength is between the nut and the rod if less than the entire rod is engaged? I can't enlarge the holes in the baseplate for couplers without affecting the anchor rods and I am leery of welding on an extension of the threaded rod.