Other than strength and composition not a lot. Grade 60 tends to be less ductile, but is most common for both main rfg and stirrups. The metallurgy for grade 60 has improved so that they aren't as 'brittle' and I haven't seen one 'break' for decades. About 40 years ago, I dropped a grade 60 stirrup in the winter and it broke into two parts after it hit the ground... some engineers still don't like using grade 60 for stirrups.
I am looking at switching our design process from grade 40 to 60. It would be mainly used just on bottom mat rebar in slab on grade construction. Previously they have always specified 40, but I thought it may be worth switching to 60 to take some of the steel requirement out of the foundation. I am trying to look at the cost difference between the 2 grades oppesed to the labor to assemble the additional steel.
We have always specified 60 ksi bar over 40 and have never ran into any cost issues with it. Several contractors (who normally complain about every cost we put into the job) have also never taken issue with this specification.
I don't know the exact cost figures or cost indexes, but I do not think the cost is significant anymore to worry about.
PE, SE
Eastern United States
"If a builder builds a house for someone, and does not construct it properly, and the house which he built falls in and kills its owner, then that builder shall be put to death!"
~Code of Hammurabi
I thought they didn't even make 40 ksi rebar anymore. As far as I know (talking to some older engineers in the office), 60 ksi has been predominantly (if not exclusively) used for decades.
I am going off of old specs from the 80's that we still use. I am trying to update evrything. It sounds like I should start specifying out 60. Thnaks for the responses. It is helpful.
I checked with two suppliers in Edmonton, Alberta. They sell only Grade 400 (Metric) which is roughly equivalent to Grade 60 (Imperial). You cannot buy Grade 40 rebar from these two suppliers, even for stirrups or ties, but it may be available elsewhere.
While I find the Net to be an amazing wealth of info - voice to voice or eyeball to eyeball will often get you much further down the path you are pursuing. And yes - I am an old fart - almost 60 - but I still do VB programming and structural engineering!!
Mike.. what I meant was that it is orders of magnitude faster to google a company's name than to pull out a phone book. I'm much younger than you, I'm sure, but I too prefer to talk to someone on the phone. I just look up the number online.
In Australia, the only market for the lower strength, higher ductility, more easily site bent reinforcement is for swimming pools. Otherwise, our standard grade is now 500 MPa, or about 70 ksi.
Off topic: I think Mikes point is that you should get a quote from a real person/entity who's job it is to happily sell you some steel and ACTUALLY WANTS to tell you because of this. The phone is the easiest way to do this after you found the phone #. Use google or the phone book (which ever your preference) to get the # and call a real person who already knows the answer because they have the price chart in front of them. And, FWIW, email or googling is a good way to NOT establish a real relationship/contact/business referral when compared to speaking to a real person. I have never seen a market price chart for commodity building materials online -EVER, nor would I trust it if I did. And... Nothing can beat a phone call for speed when you want an answer for something like this. Sorry, Rant: -OFF-
On topic: I have been requested to use 40ksi bar to save money on ICF walls from a specialty ICF contractor. I don't know if they buy stock by the train car load or what but 1) it is still available (subject to market) 2) there apparently is a price difference to some people (maybe labor only? I know they preferred lots of small bar vs. less big bar)
To the OP: Please post the answer you find after you call.
Per Structuremag "Most deformed reinforcing steel used in cast-in-place concrete construction today is ASTM A615 Grade 60 reinforcing steel." You can see the artical at
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
Thanks Garth for the article. The section on cost was interesting even though it was comparing 75ksi to 60ksi (not 40ksi). Material cost was increased 2% but the required material was decreased by 20%.
