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Re: CONC - Stripping of Deck Forms

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It has always been my understanding that strength may develop prior to
the 28 days but the full elastic properties of the material will not
develop until the full 28 days, that is why there is a 28 day
requriement.  You can get some deformation if stressed excessively prior
to that point.  I have run into this many times.  Usually, I allow them
to strip the forms in a few days but they must still have posts in place
in a pattern so as not to deform the members.

I agree with previous posts, it should be defined in the specs or plans
and the contractor is obliged to follow those requirements.

Bill Sherman wrote:

> > The contractor wants to know if he can strip the forms after 7 days,
> assuming the concrete has reached full design strength. <
> How has it been confirmed that the concrete has achieved its full
> design
> strength?  ACI 301-2.3.4 addresses removal of forms based on design
> strength.
> Some engineers allow removal of forms even before full design strength
> has
> been reached if the element is protected from live loads.  Some
> responders
> have mentioned creep/ modulus of elasticity - but I believe modulus of
> elasticity is proportional to strength; thus if it has developed full
> design
> strength, shouldn't it also have developed its modulus of elasticity?
> I don't
> see it as a problem if strength development has been documented.