Pull out strength for chemical anchor in hollow concrete blocks 1

[rteja]

I want to submit a report verifying the pull out strength of chemical anchor bolt installed on a masonry wall made of hollow concrete blocks.
The HILTI software has a provision for this, but only for a few pre-defined hollow block geometries. It doesn't allow for customization of brick size.
My hollow brick face thickness is around 80mm, but the required anchorage depth will be more than that.
How can i calculate pull-out strength of a chemically fixed anchor in this case?
I Appreciate if you can give me any references or sample calculations for this.

 

[klaus.]

Well 80mm not very much to put an anchor in
In doubt you have to make pullout test...or contact Hilti technical guys to see if they can help

 

[rteja]

HILTI suggested for a pullout test

 

[klaus.]

yes...pullout test is the best ...and easy to do

 

[jayrod12]

And if you need more than 80mm and you don't have that amount of depth, perhaps you need more anchors.

 

[MrHershey]

When I've done these situations you have to use a mesh tube (Hilti's is HIT-SC I think) that the epoxy seeps out of inside the hollow cavity and then dries to form a plug that resists pullout (see image below).

From a behavior standpoint it isn't really a chemical/epoxy anchor anymore at that point, functions more like a drywall anchor. Strength values should be in the technical literature and I don't think vary much based on embedment or spacing since strength is mainly governed by the dried epoxy plug bearing on the interior side of the face shell.