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Post-installed anchor bolts 3

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WWTEng

Structural
Nov 2, 2011
391
Concrete was poured without the anchor-rods in place. Now I have to specify some post-installed anchors. I have some frame columns where I intend to use Hilti adhesive anchors. But I also have several other columns which carry vertical load only. Is the use of expansion or sleeve anchors as anchor bolts acceptable?
 
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It all comes down to workmanship. There are layers of safety factors due to inconsistencies in how these are installed.

This is similar to masonry. Look at the numbers- a utility grade 2X4 has a higher compression strength (in psi) than masonry. This is primarily due to the human factor in laying block (or for post-installed anchors).
 
MSSquared
For your concerns re: edge distances & mechanical anchors, I agree with regard to expansion anchors, but there are mechanical "undercut" anchors. It's a more complicated installation but they essentially drill out a pocket at the end and behave more similarly to a cast in place anchor.
Check out Hilti HDAs for an example. I believe you can get better capacities out of one of these than any of the epoxies based on the same edge distance, geometry, etc.
Of course, they're more expensive and harder to install than epoxy.
 
Hilti's undercut anchors were used to retrofit all the ceiling suspension anchors in the Big Dig tunnel after the adhesive anchors were found to be defective.
 
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