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[SEAOC] Re: [SEAOC] rebar costs

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On Fri, 8 Nov 1996 HARRISENGR(--nospam--at) wrote:

>      During a structural observation today the concrete contractor told me
> the differece in cost between 40 and 60ksi rebar is $5.00 per ton ( 1400 feet
> of number 4 bar ).
>      Is this correct? If so, why even bother with 40 ksi rebar as is common
> with number 3 and 4 rebar ? The contractor said lately local suppliers had
> 60ksi readily available in the smaller sizes. The application today was a
> non-structural slab on grade with number 3 rebar at 18" O.C..
>      I would value your thoughts.

I don't think it matters in slabs on grade, however, I think the blanket 
specification that we see so often of "all number 5 and smaller shall be 
Grade 40..." has got to the point where many of us just do it without 
knowing why. I always specify "all stirrups and ties shall be Grade 
40...", and the reason is bendability. I have seen cracks on the outer 
radii of Grade 60 stirrups bent to the smaller allowable radius, hence, I 
design Av for 40 ksi, I spec. it, and I expect to get it. 

I often have contractors tell me that Grade 40 isn't available. What that 
usually means is that their supplier doesn't stock it, ususally because 
they want to hold down their inventory. In fact, it's readily available.


.    .    .   .   .  .  .  .  . . . . . ...........................
Bob Shilling, SE             Berkeley, CA          shilling(--nospam--at)
KK6QQ         				                   MSA S-10
'91 R100 Clasic, "Tornado"    ABC#2063                    DoD# 1195
      "This alligator walks into a bar and ..."   Horizon Kent