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Tolerances for Anchor Rods Holes

Tolerances for Anchor Rods Holes

Does anyone know about tolerances for specified holes for anchor rods?
I mean, if on shop drawings is specified a diametre for holes, what is the tolerance (in diametre) for making them?
Any reference that adresses this item? Because AISC recomends diametres of holes depending on anchor rod diametre, but AISC doesnt say anything about the tolerance in diametres of holes.

Thank you in advance.

RE: Tolerances for Anchor Rods Holes

Not a useful answer, but just a comment:

What sometimes gets applied is the tolerance for structural bolt holes, because anchor rods get called "anchor bolts".  This tolerance is way too stringent.

Texas DOT uses a tolerance of +1/8" (3 mm) -0 for bridge anchor rod holes, for whatever that's worth.


Eng-Tips guidelines:  FAQ731-376

RE: Tolerances for Anchor Rods Holes

I am curious to know why this is an issue. The holes given in the 3rd Ed. Table 14-2 are very much larger than the bolt, for good reason. Given no other guidance, I'd say 1/8" either way shouldn't cause a problem.

You should post this to the AISC Steel Solutions Center. Those guys get an answer back to you in a hurry.

I thought you were going to ask the typically more relevant question of anchor rod placement tolerances. Many people don't think about it and use the ACI 117(?) tolerances rather than the AISC Code of Standard Practice. The ACI standard, I believe, is 1", a ludicrous number. The AISC number is much smaller. Most folks I know are going toward the AISC number.


RE: Tolerances for Anchor Rods Holes

i don't think it is practicable to ask the concrete contractor to meet the tolerance specified in AISC codes. usually, the holes on baseplate shall have 0.5" tolerance for steel erection. and steel washer plates are required. these washer plates shall be welded to the base plate after erection.

RE: Tolerances for Anchor Rods Holes

Per the ASD 9th edition in section 7.5.1 of the AISC Code of Standard Practice the distance between two bolts in the same group should not vary by more than 1/8".  Elsewhere in the manual (page 4-131) the suggessted hole size for anchor bolts of 3/4" to 2" diameter can be made oversize by 5/16" to 1/2", so I don't really see the tolerance of the hole itself being an issue unless you are maybe punching or burning holes.

You could probably detail the drawings with a plus or minus 1/16" tolerance and meet code requirements.


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