Headed Anchors in Concrete
Headed Anchors in Concrete
(OP)
I have a few questions that I'm hoping some of you may have some insight into. FYI, I'm basing my questions off of ACI 318-05.
1) Imagine that a 12" long anchor is being cast 6" into a slab. A 6" secondary pour is then cast atop the original slab once cured, thus creating a horizontal cold joint halfway down the anchor. If the anchor is subjected to tensile loads, how will the shear transfer through the joint? Is the effective depth the full 12" or only 6"?
2) Obviously the ACI code is very vague when it comes to the potential strength increase by adding supplementary reinforcement. Has there been any recent studies or papers published that quantify the potential increase? I only have the "Reverse Cyclic Loading" paper from the early 80's.
Thanks in advance.
1) Imagine that a 12" long anchor is being cast 6" into a slab. A 6" secondary pour is then cast atop the original slab once cured, thus creating a horizontal cold joint halfway down the anchor. If the anchor is subjected to tensile loads, how will the shear transfer through the joint? Is the effective depth the full 12" or only 6"?
2) Obviously the ACI code is very vague when it comes to the potential strength increase by adding supplementary reinforcement. Has there been any recent studies or papers published that quantify the potential increase? I only have the "Reverse Cyclic Loading" paper from the early 80's.
Thanks in advance.






RE: Headed Anchors in Concrete
RE: Headed Anchors in Concrete
Regarding the cold joint, if the head of the anchor is below the cold joint, it would seem to me that there would be a compression load transfer between the two surfaces in order to continue development of the shear cone until the failure plane reaches a free edge or yields the anchor. I suppose this would depend upon on edge distance, so this should be accounted for.
Reinforcement contributes to pullout strength by intercepting the shear cone by transferring load to the bar through shear friction. Apply the provisions of ACI318 Chapter 11 for guidance for the shear friction design method.
RE: Headed Anchors in Concrete