Anchor Bolt Hole Sizes 1

[BSVBD]

(Considering ONLY 3/4" Anchor-Bolts - for example)

AISC 13th, Table 14-2 provides "Recommended MAXIMUM Sizes for Anchor-Rod Holes in Base Plates.

Considering the 3/4" anchor bolt, this table allows the hole to be 9/16" larger than the bolt.

AISC 9th, 4-130 says "Hole sizes for anchor bolts are normally made oversize to facilitate erection as follows: Bolts 3/4 to 1 in. - 5/16 in. oversize..."

When would one specify the MAXIMUM Oversize of 9/16" versus the "normal" Oversize of 5/16"?

Over the years I've seen various specifications. I'm trying to assist a General Contractor with establishing a reasonable standard.

Please include and cautions I may not be considering.

Thank you!

 

[MotorCity]

I (almost) always specify the maximum hole size......cuts down on the phone calls about how to fix mislocated anchor rods

 

[Lomarandil]

Agreed, always spec the maximum to give your installation as much tolerance is possible.

The designer should know to account for this, and may require welded washers for even shear transfer. Whether they do or not -- has been a mixed bag in my experience.

----
The name is a long story -- just call me Lo.

 

[dik]

From my project notes (added: works with non-proportional fonts):


HOLES IN BASE PLATES, SIZE AND THICKNESS OF WASHER SHALL BE AS FOLLOWS

AB DIA BPL HOLE DIA MIN WASHER DIA MIN WASHER THICK
(IN) (IN) (IN) (IN)
1/2 1 1-3/4 3/16
5/8 1-1/8 1-3/4 1/4
3/4 1-5/16 2 1/4
7/8 1-9/16 2-1/2 5/16
1 1-13/16 3 3/8
1-1/4 2-1/16 3 1/2
1-1/2 2-5/16 3-1/2 1/2

Dik