Dear Hamed,
you can prescribe temperatures below 0 in Transport, no problem with that.

However, if you are interested in the influence of frost on hydration heat development, as far as I know, the properties generated by ConMix do NOT specifically consider that. You would most likely need to adjust the properties manually. Even the heat corresponding to the phase change has to be taken into account by adjusting the Capacity function.

Similarly, when you later import the Transport results into your Static or Creep model, you have to define the corresponding functions for the material model with teperature-dependent properties (prototype NLCem2UserWithTempDepProps) by yourself.

Regards.

Dear Hamed,
if you plan to use the CCTransport material model with CerHyd and ConMix, you have to upgrade to the current ATENA version, 5.6.1h. Although the CCTransport material had already been available in ATENA 5.1, its advanced options (like all CerHyd ones) were not fully implemented yet.

ConMix is include in the current ATENA installation and starts from the CCTransport material dialog when you choose "File".

Once you install the current version, I suggest to look at the hydration example model (ATENA Science Example Manual, 3.2 Heat and Moisture Transport Analysis incl. Hydration - both the document and the referred example model are included in ATENA installation).

If your expired ATENA maintenance does not allow you to use the current version, please contact us for a renewal offer.

Regards.

Dear Dr. Pryl,

I hope this message finds you well. I want to apply monthly time-dependent temperature variations to a part of an arch dam in the transport model.

1- From what I could understand from the GID manual, the only way to define temperature-time curve is through using the “Moisture temperature boundary for surface” condition or is there another way too?

2- If the “Moisture temperature boundary for surface” is used, ambient temperature function can be defined from “function from material”. It’s been specified in this dialog that” this material is only for writing user function to the input file, do not assign it to the model”. This being the case, how can I assign the material to different parts of the dam?

Moreover, in the static model and the “Reinforced Concrete” material dialog, why there are 6 smeared reinforcements?, what do they denote?

Many thanks for all your support.

Best Regards,
Hamed

Dear Dr. Pryl,

Many thanks for your prompt answer and the constructive comments. I simply want to define a curve showing temperature variations as a function of time and apply it to a surface, i.e.:

Time (days)       Temperatures (degrees centigrade)
30                      0
60                     -1
90                    4.2
120                   11.7
150                    17
180                  22.4
210                  26.2
240                  26.9
270                  24.2
300                  17.7
330                  10.8
360                    4.7

how can I define this curve in ATENA-GID interface?
Is it possible to use the fire boundary element condition to define the curve by manually adjusting the values, or is there a better way?

Moreover, I guess I have to use smaller load steps or use finer meshes in the model to capture below zero temperatures, am I right?

Best Regards,
Hamed

Dear Dr. Pryl,

Sorry for my late reply.

1. Temperatures mentioned in the previous post are average monthly temperatures of the air obtained from meteorology measurements and l’ve ASSUMED them to be air temperatures near the concrete surface.

I would be really grateful if you could explain about the different cases that you’ve mentioned in the previous post and the possible reliance of the obtained results on the respective case considered.

2. I want to investigate several cases including (a) long-term temperatures (year cycles) and (b) day cycles where there are usually gradient changes, for example between -10 and 10 degrees centigrade.

3. I’ve manually edited the fire and boundary conditions to define the time-temperature curve. I do not know any other way.

Many thanks for all your support.

Best Regards,
Hamed

Dear Dr. Pryl,

Many thanks for your email.

The problem is that I don’t know how the “functions” work.

If the moisture temperature condition is activated, the default value for the ambient temperature is equal to 20 degrees centigrade and it is reasonable to consider temperature variations as coefficients multiplied to the ambient temperature to be used as Y values along with X values (which should be time values in seconds) in a tabular form and there is no need to use the X and Y multipliers in the “functions” dialog box.

For example if I want to define that after an hour the temperature rises to 25 degrees centigrade should I define it as follows?:

X (s)                   Y (temp)
0                           1
3600                    1.25

X multiplier =1
Y multiplier=1?

I feel that I’m missing something here. I really appreciate all the guidance you provide.

Best Regards,
Hamed

Dear Dr. Pryl,

Unfortunately, I haven’t been able to figure out how the functions work. I’m familiar with the total condition. I’ve used it before in the “fire boundary for surface” condition.

I just don’t know how the values in the functions dialog box work. If I want to apply “moisture temperature condition to a surface with an initial ambient temperature of 20 which rises to for example 30 degrees in two hours what the values should be in the functions dialog box (the initial temperature of concrete is also 20 degrees centigrade)? Should they be as follows?:

X (time, unit seconds)                    Y (temperature, unit degrees centigrade)
0                                                      20
7200s                                               30
Multiplier X=1
Multiplier Y=1

OR

X (time, unit seconds)                     Y (temperature, unit degrees centigrade)
0                                                      1 (20 divided by the initial ambient temperature)
7200s                                              1.5 (30 dived by the initial ambient temperature)
Multiplier X=1
Multiplier Y=1

When I define any of these, I get the error” underflow or overflow arithmetic operation” in the very first step of the analysis.

Best Regards,
Hamed

Dear Dr. Pryl,

1- I define the initial temperature for the concrete itself from the data-material-solid concrete-cctransportmatrial-initial temperature tab. For the “moisture temperature boundary for surface” condition the default value for the initial temperature is 20 degrees centigrade and I do not change it; I enable the ambient temperature function and define the function as I’ve mentioned in my previous post by entering the x and y data in a tabular form. I assign the condition to the surface I want but I do not assign the function to the model.

2- I fix the moisture DOF.

3- Thank you very much.

4- The mesh size and the step length vary in my model. But I don’t think the problem is related to the mesh size or the step length. I analyze my model without any problem by defining the curve using the “fire boundary for surface” condition. I just want to learn how the functions work as well.

Best Regards,
Hamed

Dear Dr. Pryl,

1- Yes I mean the ambient temperature setting.

2- I mean the note in the "functions" dialog box which says "this material is only for writing user function to the input file. Please do not assign it to the model".

Best Regards,
Hamed

Dear Dr. Pryl,

I sent the model to your email via yahoo.

Best Regards,
Hamed

Dear Hamed, if you set the parameters accordingly, I guess the condition should give you at least a reasonable approximation. Or are you specifically interested in some effects important for water and negligible for air?

Regards.