Anchor Rod and Rebar Development Length

[Althalus]

I had believed that the rebar development length formula was only for standard rebar with standard deformations. The psai (sorry, I can't type Greek letters) factors take into account epoxy coated rebar for a lower friction coefficient. So, I'd think that any other deformations would also effect the development length.

So, we have an embed plate that is almost entirely in tension. All the other cases based on dimensions would probably be the same regardless of the anchor type.

But when it comes to pullout, I'm seeing someone's calculation using rebar development length (Ch 12 of ACI 318-08) as the basis. But the bars we're using have different surface characteristics than rebar. Are those still valid if the bars in question are of smoother surface characteristics?

Additionally, the bars we have are also different than standard threaded rod. So, would Appendix D formulas for pullout be accurate?

 

[Lomarandil]

You touch on a few different topics:

Is the development of rebar different from the development of threaded rod? Yes, although the difference may not be that substantial. You could certainly envelope the development length between that of deformed bars and smooth wires or prestressing strand.

Are Appendix D formulas for pullout applicable to threaded rods? Yes(and I practically wouldn't worry about the difference between coil thread vs fine thread bars)

Are development length calculations sufficient to prove an anchorage? Not necessarily. Certainly anchorage breakout still needs to be checked (see

https://www.eng-tips.com/viewthread.cfm?qid=492081)

 

[Althalus]

The anchors being used are not threaded rod. They're fairly smooth rods.

 

[RWW0002]

If they are "fairly smooth" rods I hope they at least have a head or a nut threaded on the embedded portion - Otherwise you may have a hard time justifying any appreciable strength in tension.

If this is a headed anchor rod or some sort and it is lapped with rebar, then the rebar development length may be appropriate here. There are multiple threads on here that deal with anchor rods that lap with rebar. Here is a link to a useful paper if this is in fact your situation.

https://www.sefindia.org/forum/file...nforcement_a_petrolium_project_papers_199.pdf