Concrete anchor supplemental reinforcing

[DTS419]

Is there an acceptable way to account for or provide supplemental reinforcing for a concrete anchor? As in the attached sketch, a rebar is placed perpendicular to the anchor so that it runs continuously through the failure cone. Not sure if shear-friction would apply since the bar wouldn't be developed on both sides of each failure plane.

 

[Cpw628]

My understanding of the topic is that yes you can (kinda), but the current research/understanding is still somewhat limited. The best reference I have is going to be ACI 318-19, Section 17.5.2.1, however this is fairly strict and requires for an all or nothing approach. They also talk about it in another form below.

https://www.eng-tips.com/viewthread.cfm?qid=478944

Other than that, I believe there are some extra provisions and factors that you can apply to increase capacity depending on the reinforcement, but they don’t do too much.

 

[icebloom]

The ACI section listed by Cpw628 contains guidance on supplementary reinforcement. Another resource would be FIB Design Guide 58 or the Eurocode EN 1992-4 - most of the research for anchor design that the CCD method (which is what ACI and Eurocode use) has come out of Europe. Intuitively you'd also think shear friction can apply, however this is not listed in any of the anchoring codes world wide as a method to preclude breakout. All the codes and other references such as the book Anchorage in Concrete Construction by Eligehausen state that reinforcement to prevent either tension or shear breakout has to be parallel to the load direction. Both ACI and Eurocode (and FIB 58) have guidance on how to provide this.