Concrete 02 input data

[JKLee]

Hello
I have a question about concrete 02.
I am conducting mechanical analysis after looking at the experimental paper, but only the concrete strength can be known in the experimental paper.

I want to know how to input other input values.

So far, I've looked at the STKO example and entered an arbitrary value, but I'd like to know how to calculate the input value for accurate analysis.

Can you tell me how to calculate or which part to study?

[marafini.f]

Hi JKLee,

I talked about Concrete02 in week13 of GetStarted with OpenSees and STKO. There are indications to calculate $lambda $ft $Ets. As for $fpc $epsc0 $fpcu $epsU, either you have experimental value or you can reference any norm which normally provides empirical formulations for these parameters (like Eurocode 2)

Immagine1.png (72.4 KiB) Viewed 4942 times

Let us know how it goes.
Enjoy your modelling.
Francesca

[JKLee]

Thank you for your answer.

I'm not good at English, so I didn't watch YouTube videos well, but now I know how to put the input value of concrete02.

I saw Eurocode 2, and the epcU value was presented small, so I'm studying this part while looking for other concrete models.

I have an additional question.

In the ongoing analysis, the results are stiff compared to the experimental data.

At first, I thought it was an experimental problem, but as I interpreted several models, I found that P-delta effect was not considered.

I heard that 'disBeamColumn-transType-P-Delta' considers large Delta and does not consider small Delta, but how does STKO analysis the small delta effect?

[STKO Team]

To account for small-delta effects you just need to discretize your member, so that P-LargeDelta in every mesh become a P-smallDelta for the entire member.

[JKLee]

I'm sorry, but I don't know that I understood it well.

I understood that I applied the Pdelta effect by doing a lot of mesh.

Did I understand correctly?

Then, I modeled the column of 2000mm at 50mm along the strap interval, but did my analysis result take into account the Pdelta effect?

Or I understand that the method I use is mesh only along the axial direction of the member, but should I use another method?

[STKO Team]

You just need to discretize your beam along its axial direction

[ankurjain1992]

As can be understood from the Video and Presentation, lambda = ratio between unloading slope at epscU and initial slope at epsc0 = (2*fpcU/epscU)/(2*fpc/epsc0) .......... Eq.1

or lambda = (fpcU/epscU)/(2*fpc/epsc0).......... Eq.2

Which Equation is correct ?

And it can vary from 0.05 to 0.2.

[STKO Team]

I don't understand your question... lambda is a value that you choose.
0.1 is typically fine for concrete

[ankurjain1992]

Lambda is a ratio. So how to calculate it. Many are using 0.1. But how we got 0.1.

[Clarabella]

Experimental data and literature