Installing Screened Epoxy Anchor

[XR250]

I am working on a job where the contractor will be installing various angle iron ledgers on hollow 8" CMU walls. I am specifying 1/2"Ø Hilti HY70 screened anchors. What protocol are you guys using for the fabrication of the angles and installation? Drill 9/16"Ø holes in the angle iron, tack it up, mark the holes, take it down drill the 11/16"Ø holes in the CMU and install screen tubes, tack the ledger back up, squirt epoxy and then install the rods? What happens if the drill bit walks a little and the holes ends up slightly off?

Seems if you did it any other way, you would have to drill oversized holes in the angle iron for the screen tubes (would also have to cut the lip off the tube) and then have to weld plate washers on to bring them down to the correct diameter. That would also add a little eccentricity to the bolt.

Thoughts?

 

[MrHershey]

That's pretty much the process. And that's been a frequent complaint I get with epoxy anchors. For the larger anchors the bit size is typically 1/8" bigger rather than 1/16" like a standard hole, so process is the same as you described. Very frequently get asked to switch to wedge anchors for that reason. Try to comply when I can (or just spec them in the first place) but tough when you need the epoxy for strength.

On a recent job when we specified the HY70 screen anchors for some hollow block, they actually requested to switch to Hilti's HLC anchor which is a sleeve anchor. Acts almost like a drywall anchor in that the sleeve expands as you torque and travels back up the shank until it's clamped against the inside of the face shell. My recollection is strength was similar.

 

[XR250]

The capacity of HLC anchors is surprisingly high. Apparently, they are not allowed to be installed in mortar joints so contractor will have to pay extra attention to that.
Thanks