Material doesn't matter in deflection calculation of RC beams?

[b_isufiFNCSG]

Hi, I am trying to learn more about the required reinforcement module before I use it in my projects. I am using concrete C30/37 according to Eurocode, but I created also another material called C30/37cracked in which the modulus of elasticity is halved for convenience during seismic analysis. I wanted to know if this halving would affect the cracking and deformation checks but somehow it doesn't. How is this possible? Does Robot somehow know that my material is still C30/37 but I reduced the modulus just for seismic analysis? Thanks in advance.

[b_isufiFNCSG]

Here is the model if it helps. Thanks!

[Simau]

Hi @b_isufiFNCSG 

In my understanding you must do 2 models:
Model with halfed modulus is used to design the structure and check it's displacement under  seismic loads
Model with not halfed modulus is used to check crackings and deflections under SLS.

[b_isufiFNCSG]

My understanding was that too, until I did the actual comparison of the results (see the model I shared). This model  seems to indicate that the result is the same in terms of cracking for both concrete materials (C30/37 and C30/37cracked). This is quite surprising to me and I really appreciate your help in understanding what is really happening. There is no detailed report in the required reinforcement module so it is difficult to see what is happening under the hood. 

[Simau]

Could you complet your model and show us your cracking results you get for C30 and C30 cracked

[b_isufiFNCSG]

Sure, the model I shared has both materials I think but I am sharing the results here for your convenience. Both the reported deflection and cracking are the same, regardless of the material I used for the beam:

The models on the left are the same but with the beam divided into two elements (at the planted column, this is another discussion).

I hope this helps!

Thanks!

[Simau]

When running requiered reinforcement module, Robot uses only one material as defined in calculting parameters tab, then you must create 2 Calc Param, one with C30 and another for C30 cracked and apply them to each beam

But with Diagrams for members deflections are different

[Simau]

Message 7 updated

[b_isufiFNCSG]

Thank you for your answer, I really appreciate it, but I am using the calculation parameters "test" which have the option "as in a structure model" enabled, and in the required reinforcement module the materials are correctly detected as different, see figure below. Should I still have to specify two calculation parameters? What does the "as in a structure model" do? 

[Simau]

Should I still have to specify two calculation parameters?

Correct,

Go to Job preferences > Material and create 2 new mat cracked and non cracked.

Then in Calculation Parameters create 2 Calc Param and apply them to each beam

Model attached

[brisid.isufi]

Hi, I was studying the model shared by @Simau, and it seems that the issue is not solved even with two different calculation parameters. Here is a screenshot of the results:

Elements 3 and 8 still have the same deflection and the same cracking. I am sharing the revised model in which I correctly applied the materials and the calculation parameters as suggested.

Could someone please take a closer look into this? Even if this is a feature (and not a bug), it seems to me like an explanation is needed as to what "as in structural model" is supposed to do and how to correctly use the required reinforcement module to avoid mistakes. Thanks in advance!

[Simau]

Max deflections are differentes according to modulus

[brisid.isufi]

Deflections from the analysis are indeed different, but that is not the question. My question concerns RC deflections, which are not directly obtained from analysis. If you look at the maximum deflection from the reinforced concrete results in the "required member reinforcement" table, you will find the table that I shared in my previous message.

[Simau]

Maybe the development team can reply