Re-bar grade

[IFRs]

I have been told that Grade 60 is taking over the USA. Is this true? And, what are the advantages / disadvantages of Grade 60 over Grade 40? I need several hundred thousand pounds for a current project. What are the best sources? Thanks!

 

[JAE]

Grade 60 has been used in the US since the early 80's at least...possibly some in the 1970's. Grade 40 has been rare since the early 1980's.

 

[BigH]

IFRs - I suppose the most obvious is higher strength of Grade 60 over Grade 40 (Grades 420 / Grade 300 for those in metric). This will mean less steel in the structure - can have thinner/smaller sections.

 

[MichSt]

Grade 60 is the standard in bridge construction these days.

The increase in strenght in grade 60 will require you to use larger laps and development lengths as compared to grade 40. But, this will by far be offset by steel weight savings due to the increased strength as BigH mentioned.

 

[Ussuri]

BigH by Grade 420 do you mean yield at 420MPa?

Typically rebar in the UK is 460MPa for high yield. But even that is now being replaced by 500MPa steel.

 

[BigH]

Ussuri - I was using the ASTM grades. Grade 60 translates according to ASTM A615 to Grade 420. Grade 75 becomes Grade 520 in ASTM A615. ASTM didn't do soft conversions but hard (i.e., not "exactly".) This idea of different steels is a problem internationally in my view. When I was in Laos, we required Grade 60 steel. No steel was going to come from USA - but from Thailand or Vietnam. Still Grade 60 was specified. The near Thai equivalent was something like 1% lower in minimum strength values than the ASTM grade - the next Thai grade up (and special order) was well above. So contractors and us had to be careful - ordering Thai steel but with specific heat numbers having minimum test values exceeding Thai and ASTM. The world should adopt a more uniform code of material properties. On my current job where again, ASTM is specified, I will be having to review European steel specs to ASTM to confirm compliance.