Tack welding rods
Tack welding rods
(OP)
I'm detailing anchor bolts for column base plates. I've got a threaded rod embeded in the concrete footing. For anchorage of the rod, I do not want to bend or hook the rod. 2 questions for everyone...
1 - I've seen an embeded nut, a nut and washer, 2 nuts sandwiching a plate, and 2 nuts with 2 washers sandwiching a plate. Any opinions?
2 - To keep the nut in place, I've seen tack welding and burring the threads of the rod. Preferences? What rods can and cannot be tack welded? (ASTM A36, A193 B7, A307, A354, A449, A572, A588, A687, F1554)
I guess it would be nice to know what the difference between all the materials is as well (if you have some extra time on your hands).
1 - I've seen an embeded nut, a nut and washer, 2 nuts sandwiching a plate, and 2 nuts with 2 washers sandwiching a plate. Any opinions?
2 - To keep the nut in place, I've seen tack welding and burring the threads of the rod. Preferences? What rods can and cannot be tack welded? (ASTM A36, A193 B7, A307, A354, A449, A572, A588, A687, F1554)
I guess it would be nice to know what the difference between all the materials is as well (if you have some extra time on your hands).






RE: Tack welding rods
2.) We show it tack welded. I don't see a reason to burr the threads (if it's welded), but it won't hurt anything if they do. F1554 is the standard material for anchor rods. Gr 36 is weldable. Gr 55 is only weldable if you spec the S1 supplement. I don't believe Gr 105 is weldable.
F1554 is the comm
RE: Tack welding rods
Tack welding a nut or nut+plate washer is not a problem
RE: Tack welding rods
RE: Tack welding rods
I believe the speaker mentioned that when you order F1554 36ksi rods you are more likely going to get 55 ksi rods (because the suppliers think giving a higher grade is better). He said, "If you are going to need the rods to be welded then you need to spec F1554 55ksi with the S1 supplement". Not sure if this is true or not.
Our standard detail is to use double nuts and washers.... But you run the risk of these not being installed (happened to me once before).
RE: Tack welding rods
RE: Tack welding rods
RE: Tack welding rods
Bring the nut flush with the end surface of the rod. Weld it on the end. You can add or plate washer or not, though the washer will add load capacity as StructuralEIT noted.
RE: Tack welding rods
RE: Tack welding rods
The double nut would then be the ideal detail. It would eliminate the need for tack welding the rod (which may or may not be OK), and avoid welding onto the nut and washer (which no one likes).
It also sounds like no one is particulary concerned about tacking to the rod (even if it is "weldable" or not), nuts and washers as long as the tack weld is away from the loaded areas (like the bottom of the nut).