ACI318 for Anchor to Masonry Design?

[EngStuff]

I was looking through Hilti Masonry Anchor Design Guide and saw they are using ACI318 to design their anchors to masonry with a few modifications.

https://www.hilti.com/content/dam/urgent-folder/w1/pdf/tech-guides/AC 58_Anchor Design Guide.pdf

This is my first time seeing it designed this way, I always used TMS. A couple questions

1. Is it acceptable for us to start using the ACI to design anchors into masonry and not TMS?

2. What code book year did they start allowing the design of anchors to masonry using ACI318. (follow up question 3)

3. In the Design guide, it says "The adoption and adaptation of ACI 318’s Concrete
Capacity Design (CCD) method for the design of post
installed anchors into masonry base materials."

​

It seems like that was last/this year? Should we still hold off on adopting it until the building codes are updated for specific states?

 

[Eng16080]

I don't have any answers to this, but I have contemplated using ACI for anchorage design of masonry. It seems like if you were to anchor directly into the face shell of the cmu (which is concrete anyway) and you weren't affected by any of the complications of cmu (like grout fill and mortar joints being a slightly different material and not being monolithic), then I don't see an issue.

If the anchor was close to a joint or extended through the face shell into grout, then perhaps it wouldn't exactly be applicable. Still, if you were to take the lower strength of the concrete, mortar, and grout, and design assuming it was solid concrete, I would expect the result might be similar. Not sure if I would do it that way. Just speculating.

 

[Lomarandil]

I've had the same thoughts as 16080, but have always referred to TMS

 

[lexpatrie]

I would hesitate.

That said, and perhaps unrelated to the question, my impression of the majority of Hilti products is they are tested, and then the various safety factors are applied, rather than "engineered" and then any further calculations are based on the testing. I would argue that the ACI method is not all that different, as of 2000 there was a lot of testing of "shallow" anchorages and then various interaction equations were derived from the testing, then we do calculations based on that testing, so there's not anything fishy about the process, it's substantially similar to the ACI method (testing leveraged into design equations).

As you are probably aware, there was some concern with "light" anchors and the side-face blowout calculations not being representative for the repetitive (sill plate) connections, circa 2000-2006?. I think SEAOC eventually got some revisions, or the ACI method switched to more of a steel base plate anchorage, embed plate, and kind of walked away from the wood mudsill anchors.

FAQ: (freshly minted) - 2010 - Anchor Bolts in Light-Frame Construction at Small Edge Distances, Seismology Committee, Structure Magazine, August 2010.

Direct Link: Anchor Bolts in Light-Frame Construction at Small Edge Distances, Seismology Committee, Structure Magazine, August 2010.

 

[slickdeals]

I recently looked into this and they're using AC58.