All-thread Rebars

[abusementpark]

I've seen these threaded rebars that have the same minimum diameter as regular deformed bars (i.e. #5,#6, etc), but they instead have a threaded surface.

Assuming comparable material grades, can these be used interchangeably with regular deformed bars? I guess the real question is do they development tension all the same as a regular deformed bar?

Here is a manufacturer's example.

http://www.williamsform.com/Threaded_Bars/Grade_75_All-Thread_Rebar/grade_75_all-thread_rebar.html

 

[civeng80]

These are used as ties for concrete formwork.

I wouldn't use these for rebar they are much more expensive for starters!

 

[msquared48]

I think they are also use as local extenders, or primary vertical tension bars in some proprietary wood shearwall holddown systems.

I would not use them as rebar in concrete either.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[ToadJones]

I damned near used those things on a job once....If I remember they make high strength bars that can be used a anchor bolts. You can use the threaded bars with an embedded anchor plate/nut assembly.

I was going to use them on big utility poles that were already fab'd and the design loads changed. The poles checked out fine but the anchor rods needed to be larger or a higher strength. The holes were already in the base plates and they were galvanized. I was going to go to those rods rather than have high strength anchors fab'd the traditional way.

 

[Lion06]

I know Williams 150 ksi threaded bars meet the deformation standards of ASTM A615. They don't say so for the 75 ksi bars. I wonder what is different about the threads.

These high strength all-thread bars are commonly used as micropile reinforcing around here.

 

[SrVaro]

I have not used these for concrete but I have for within auger cast piles. We had deep piles and an extremrly low head clearance within an existing factory. This type of bar allowed multiple quick splices within the re-bar cage during installation within the pile.

The threads vs the deformed bar was looked at, as mentioned above there is no note that the Gr 75 bar meet the standards, but we felt comfortable with the threads for the grout.

I did not hear much concren over the increased costs, but I was lucky enough to be working with the owner and contractor together to develop a solution t the low head clearance.

 

[DTGT2002]

The link to the Williams bar listed above does indicate it meets the A615 standard.

While primarily marketed first as formwork materials compatible with remaining in place, these threaded bars have been used for reinforcing for some time.

They should not be confused with standard coil rod or threaded rod and special care should be taken to recognize challenges with the format - such as challenges in bending the bar as noted on the Williams link above.

 

[a2mfk]

I think as Mike said they'd be useful for in tension and uplift connections. You could get the full development of rebar, even lapped with rebar in a wall, column, footing, and then project out of the surface of the concrete to connect to a plate... Basically where I have used all-thread rods and developed them into concrete I think these would be a better alternative.

Anyone know how available they are nationwide?

 

[Lion06]

DTGT-
Where in the above link does it say that the threads conform to A615?

 

[Lion06]

I called Williams and they said the threads on the Gr. 75 all-threads do meet A615.

 

[a2mfk]

So what does that mean exactly? If you can't use the threads then you have fancy rebar...?

 

[DTGT2002]

The title of each chart giving the specs for the bar lists A615.

I would assume you could get heat numbers and tthe like if you contacted them.

The data they show is more than what one would commonly find from stock bar suppliers (online), but they are working their unique deformation patterns in a similar fashion. Bars are available with threading that looks almost identical to common deformations, but does thread into special couplers and nuts.

I've not read it recently, but it is probably worth all of our time to reacd the ASTM specs we call to.

 

[dik]

I've used Dywidag threadbars often... great cost, but the actual nuts and splicing sleeves are expensive. Great product and can get in high strength, also.

Dik

 

[a2mfk]

Read ASTM specs? Only if I am being punished or suffering from insomnia

 

[abusementpark]

I guess I am a little confused about what distinguishes these things from your typical thread rods. Technically per AISC Design Guide #1, don't you not get any tension development capacity for a regular threaded rod (no plate at the end) embedded in concrete? Whereas, with these type of threaded bars, the manufacturers are saying these are as good or better than regular deformed rebars for tension development.

What is it about the threads of these bars that allows for the tension development into concrete that regular threaded rods do not get?

 

[Lion06]

The threads are deep and coarse. Typical threaded rods have tighter threads that are not as deep. As far as I know, they don't meet the requirements of A615. Also, you are correct in that App. D doesn't recognize regular threaded rods as having any capacity without a nut or plate.

 

[slickdeals]

Does it mean that if I replace a threaded rod with nut/washer with an all thread bar that meets the requirements of ASTM A615, then I don't have to use Appendix D?

 

[dik]

I would suggest that that's the case...

Dik