Anchor Pull Tests

[SteelPE]

Recently I received a report from Hilti in regards to some field tests that were performed on some field installed anchors into a multi-wythe clay brick exterior wall. ¬ The test was done to figure out if the anchors can be used to support some exterior features. The report gives the location of the test (face of brick, mortar) and the failure load of the anchor.

How would you use this test data to design a proper anchorage system? I know that Hilti uses a FS of 5 with the proposed system, but how would one determine the shear capacity of the anchors? By using their technical guide? Or is there another acceptable way to use this data to determine allowable anchor loads?

 

[bookowski]

I have pull tests done in multi-wythe brick done often by Hilti (for hy70). My thinking is that this is just to confirm a. the suitability of the base material (since often the brick and/or mortar are suspect) and b. that the contractor is installing them correctly. I also think it motivates the contractor to do a better job installing them since he doesn't know which ones I'll ask to be tested. Beyond that though I just go back to the Hilti published values and then make adjustments for my own comfort level based on the condition of the masonry. In my area there is a guy that does shear testing of the anchors but it's not free (and Hilti is) and is somewhat complicated so I've only done that once.

 

[SteelPE]

Well, their failure loads are at best 50% greater than their published allowable loads. So, I could apply a FS of 5 to these loads and reduce the allowable shear capacity accordingly.

 

[bookowski]

Ah, I didn't realize that your failure loads were coming back low. You may be able to find a testing company to do shear tests, ask the hilti rep. In the ny, nj, pa area I know of a company that does it.