Threaded Rod - App. D or Rebar?
Threaded Rod - App. D or Rebar?
(OP)
What is everyone's opinion on threaded rods regarding the benefit of the threads in developing the rod?
In my mind, this is what App. D was made for. How often do you see an achor rod with a nut that has no threads? If you can say the threads make it as good (or even some reliable factor smaller) than rebar, then App. D has little application.
While I believe that the threads do help the rod bond to the concrete better than a plain bar, I don't believe that it is reliable and shouldn't be counted on in design.
In my mind, this is what App. D was made for. How often do you see an achor rod with a nut that has no threads? If you can say the threads make it as good (or even some reliable factor smaller) than rebar, then App. D has little application.
While I believe that the threads do help the rod bond to the concrete better than a plain bar, I don't believe that it is reliable and shouldn't be counted on in design.






RE: Threaded Rod - App. D or Rebar?
RE: Threaded Rod - App. D or Rebar?
DaveAtkins
RE: Threaded Rod - App. D or Rebar?
RE: Threaded Rod - App. D or Rebar?
I agree with you that rebar and threaded bar need not necessarily be treated differently.
Check the following paper that I got from Hilti regarding bond strength for epoxy anchors. Hope this will help.
RE: Threaded Rod - App. D or Rebar?
Threaded bar made to A615 dimensions (such as those from SAS or Dywidag) meets the deformation requirements needed to use ACI development length calculations. These are sometimes used as anchors for very large equipment.
The intent behind headed anchor rods is that the bond all occurs at the head. It is not uncommon to apply a bond-breaker to the shaft of the anchor rod, particularly if the anchor is to be pretensioned, where bond along the rod would interfere with effective pretensioning forces. The length of unbonded rod/bar is stretched in the pretensioning process, acting as a very stiff spring to retain the tension on the anchor, as might be required for normal thermal changes.
John Turner CSP PE
CRSI Greater Southwestern Regional Manager
RE: Threaded Rod - App. D or Rebar?