Codifed stress -strain curve 1

[Shz713]

Hi,

Is there any idealized stress-strain curve in AS code for steel and prestressed tendons? I know that the values of yield and ultimate strength with corresponding Modulus are provided, but what about the strain at each corresponding stress? For instance, in EC the curve below is given with appropriate inputs both in stress and strain for steel.
The reason I need the curve is for numerical modelling, I want to define the behaviour of material to resemble their interaction bothi in tensile and compression due to applied loading. Any reference would be great.

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[Retrograde]

Refer to Section C3 of the commentary to AS3600.

 

[Shz713]

Thanks heaps for super fast reply, this is good reference (btw I found the curves to be in C6). Yet, for prestress is mentioned should be obtained from experimental/manufacturer; I think I have to assume elastic-perfectly plastic for prestress because I only have the ultimate and Young modulus of prestress.

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[Retrograde]

btw I found the curves to be in C6

Do you have the 2014 edition?

 

[Shz713]

Not unfortunately

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[rapt]

Australian material codes define the properties, and they also define 1% and .2% stress limits which will allow you to determine a stress strain curve shape.

Also, AS3600 has a formula for prestress stress at ultimate. If you plot the results of this formula for varying steel ratios you will see that it is not assumed elastic plastic.

 

[Shz713]

I was able to get the 2014v edition, the curve is based on the work of Thorendeldt, whereby in original paper the value of 'n' is defined as n = 0.8 +(Fc/17)
However, in the commentary is defined as n = Ec/(Ec-Ecp); where Ec takes different values depending if compressive strength is lesser or greater than 40 MPa. There's no explanation why is that!

Would you please mention where to access such information? I am conducting some NL analysis and would like to define the stress-strain behaviour of tendons as well. I was able to define one model based on Hsu constitutive model, but I want to get as per AS. I couldn't find an generalized value for ultimate strain of tendons at breaking force, it is only mentioned 1% of Fbp to be used at Fpy.

Cheers,

Shoot for the Moon, even if U miss, U still land among Stars!

 

[rapt]

For prestress material properties you should look in AS4672-1 and -2.

More logically, get a stress strain curve for prestressing steel and use it. That is allowed by the Australian codes and what we do in RAPT.

We also use a concrete stress strain curve which is allowed by AS3600 but not defined in the code, as you will have to do also as the rectangular block cannot be used for NL analysis.

If you question above relates to the change in the Ec formula depending on concrete strength, it is because the general formula was found to be inaccurate for strengths above 40MPa!

 

[Shz713]

Thanks for your input; What I meant was that in cases when no detailed info on prestress reo is available how to define stress-strain curve. Because not always experimental data is available, I had a look at 4672.1 and common values for Fpb and 0.1%proof force are given and mentioned about strain at these points; I need these point as well to define the curve.

I realize that Ec is given two equation based on the work by "R I Gilbert" which is okay; my concern was with regard to original equation and how it converted to that formula while the Thorendeldt paper did not mention anything about this issue!

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