Cast-in Concrete Plastic Anchor Bolt Sleeve Capacity

[JamesStephens]

In the project I’m working on, the mechanical drawings call out for a plastic sleeve around the upper part of the cast in place headed anchor bolt. This sleeve has a larger diameter than the anchor bolt and will be filled with grout once the anchor bolt is set in the correct location. This allows them to make minor alignment adjustments when mounting the mechanical unit’s base to the curb. I know Wilson Anchor Bolt Sleeve Company (

http://www.wilsonanchorboltsleeve.com)

makes sleeves for this purpose, but they don’t have any published pullout values.

I would think for shear capacity, it would be about the same as for a regular cast-in headed bolt. But for tension, it doesn’t seem like you can use ACI 318 appendix D.

Does anyone know of a similar product and/or published pullout capacities?

 

[Ron]

Not a chance you'll achieve the same pullout with a back-grouted anchor as with a drilled anchor. If the manufacturer doesn't provide pullout values for their bolts, they probably aren't very proud of the values!

Do some testing. It doesn't cost that much and you'll have some answers.

 

[BENDOG]

I don't quite see where the pullout capacity of the sleeve is a concern. If you are using a headed bolt the head should be far enough below the sleeve such that the pullout cone is not affected by the sleeve.

We use sleeves a lot for setting equipment and this has never been a concern.

 

[DTGT2002]

I was going to leave this one for someone with more design experience (as I have not sepc'd these sleeves myself), but I'll second what BENDOG says, the bolt would be longer than typical as the development or embedment length would be below the anchor pocket.

The shear capacity can be improved when the final grouting is done. The sleeves typically have a profile with various deformations meaning there would be little chance of pullout, but again, counting on the anchor depth below the sleeves seems to be prudent design.

The last time I saw these spec'd, the original goal was to have a void space at the top of anchor rod accessable after the concrete was placed. This was a superflat floor with trafffic lanes and the sleeves were to be held below the finish floor elevation and accessed after to install a couple to add threaded rod for a rack system. Due to the size of the couple, the sleeves were abandonded in favor of setting sealed couplers just below the surface. Lacking the ability to "adjust" the rod in the sleeve void space, the baseplates required adjustment for final install. Not ideal, but the floor finish requirements were determined to be more important that the required baseplate adjustments.

Good luck and hope you have enough depth in your member to accommodate the extra rod length.

Daniel

 

[weab]

Agree with Bendog.