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Re: Rebar Specs

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Chris,

The ACI 318 and CRSI (Concrete Reinforcing Steel Institute) does not explicitly bar us of Rebars conforming to ASTM A616, ASTM A617.

In fact references on the subject include rebars conforming to ASTM A616, ASTM A617 as one of the reinforcing bar types to be used in reinforced concrete.

There is no substance in the fact that the steel bars conforming to ASTM A616 or A617 are not ductile & break while bending in the field. All rebars break when cold bent (of any ASTM specification), especially larger diameter rebars if bent at less than 90 degrees. This is the reason Code allows bending under heat with the following conditions:

     - the temperature should remain within 600 to
       800 degree F.
     - the rate of cooling should be slow;
       preferably natural air cooling & no
       quenching with water. Otherwise the
       metallurgical properties are
       reported to be severely alterred.

In some reference you will find steel rebars of any of the following ASTM Specifications can be used in reinforced concrete (ref: Design of Concrete Structures., by: Winter & Nilson):

         - ASTM A615
         - ASTM A616
         - ASTM A617
         - ASTM A706.

For your interest I wish to reproduce here the summary of minimum strength requirements for the above.(ref: as noted above)

    |=======|======|===========|===============
    | ASTM  | TYPE | MIN YIELD | MIN. TENSILE |
    | SPECS |      | STRENGTH  | STRENGTH     |
    ========|===== |===========|==============|
    | A615  | GR 40| 40,000 PSI| 70,000 PSI   |
    |       | GR 60| 60,000 PSI| 90,000 PSI   |
    |       | GR 75| 75,000 PSI|100,000 PSI   |
    ===========================================
    | A616  | GR 50| 50,000 PSI| 80,000 PSI   |
    |       | GR 60| 60,000 PSI| 90,000 PSI   |
    ===========================================
    | A617  | GR 40| 40,000 PSI| 70,000 PSI   |
    |       | GR 60| 60,000 PSI| 90,000 PSI   |
    ===========================================
    | A706  | GR 60| 60,000 PSI| 80,000 PSI   |
    ===========================================

Please also note the elongation values of the rebars conforming to ASTM A616 & 617 are quite compatible with those of ASTM A615, i.e, varying from about 6 to 12 %.

So, in my opinion if the rebars of ASTM A616 & 617 are meeting the requirements of the specifications (as outlined above), there is no bar as such in using them in any reinforced concrete members.

Best regards,

SYED FAIZ AHMAD; MENGG, MASCE
SENIOR STRUCTURAL ENGINEER
SAUDI OGER LTD
RIYADH, SAUDI ARABIA.



From: "Chris Towne" <ctowne(--nospam--at)chaptech.com>
Reply-To: seaint(--nospam--at)seaint.org
To: "SEAINT List Server" <seaint(--nospam--at)seaint.org>
Subject: Rebar Specs
Date: Tue, 30 Oct 2001 14:04:17 -0500

Is there any problem with allowing the contractor to use rebar that conforms to ASTM A616 or A617 instead of A615? A616 and A617 are rail steel and axle steel. A615 is new billet steel. The project requires reinforcing for foundations, slab on grade and reinforcement for Concrete Masonry walls.

Any input is appreciated.

Chris Towne, P.E.
Chapman Technical Group
200 Sixth Avenue
St. Albans, WV 25177
Phone 304-727-5501
Fax 304-727-5580


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