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Re: 1950 Rebar

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This leads me to wonder if the limitation on maximum stresses in the rebar is
the basic reason for the durability! Less cracks, less chloride ingress and less
corrosion. I have heard some friends who had inspected some old marine
structures state that even in places where the concrete had spalled due to other
reasons, round (not deformed) bars had shown remarkably few signs of corrosion!
It has led me to wonder if, for marine structures, the ASD approach with reduced
steel limiting stress would be a better choice compared to limit state design
with exotic specifications and coatings for reinforcement. Any feedbacks would
be welcome. TIA

M. Hariharan
Engineers India Limited


Sprague, Harold O. wrote:

> Ah yes an opportunity to blow off a little dust from my books and from
> between my ears.
>
> The ASTM Designation for this steel is A15.  Bar was provided as plain or
> deformed.  Either were broken down into 3 grades of steel with properties
> listed below:
>
> Grade:                            Structural      Intermediate      Hard
> Tensile strength (ksi):         55 to 75         70 to 90           80
> Yield point (ksi):                    33                  40
> 50
> Allowable str. (ksi):                16                  18               18
>
> They could also be Rail Steel A16 which would have the same mechanical
> requirements as the A15 Hard.
>
> Regards,
> Harold O. Sprague
>
> > -----Original Message-----
> > From: Tom.Hunt(--nospam--at)d-fd.com [SMTP:Tom.Hunt(--nospam--at)d-fd.com]
> > Sent: Thursday, March 15, 2001 5:11 PM
> > To:   seaint(--nospam--at)seaint.org
> > Subject:      1950 Rebar
> >
> > I am working on rehabilitating a 1950 concrete seawater intake structure
> > that was designed per the 1946 Uniform Building Code.  The drawings call
> > out for either 2500 psi or 3000 psi concrete and the rebar is called out
> > as
> > either square bar for deformed round bars.  Does any know what rebar
> > grades
> > were used in this time period?  I know 40 ksi rebar has been around for a
> > long time but as grey as my hair is this is before my time.  I might add
> > that this structure is in amazingly good shape with little deterioration.
> > Goodos for our fathers and grandfathers.
> >
> > Thomas Hunt, S.E.
> > Duke/Fluor Daniel
> >
>