• Registered: 2011-10-11
  • Posts: 8

Topic: Concrete Temperature Dependent material properties

I have noticed that including temperature dependent concrete material properties is the main driver for increased calculation time when doing a fire analysis.
Including only temperature dependency for the reinforcement results in only a minimal increase of calculation time.
(I have done these experiments mainly with the predefined material properties)

I wish to balance a good calculation speed with an acceptable modelling of the temperature dependent properties (so I can quickly see some preliminary results and I can update the model without having to wait a day or more).
Do you know which temperature dependencies for the concrete material are the main drivers of the increased calculation time?
Have you got any suggestions about how I can increase the calculation time, while including a (simplified) temperature dependent concrete model?

Best regards,
Ruben

Quote Post 1

  • From: Cervenka
  • Registered: 2007-08-08
  • Posts: 35

Re: Concrete Temperature Dependent material properties

Dear Ruben,

I am sorry for late reply. It is difficult to say, which temperature dependent parameters play most important role in increase
in the time calculation. However, here are some general remarks:

- it is better to define the temperature dependency functions such that no parameter drops totally to zero.
  Generally I recommend to not to let the parameters drop below 1% of the original value (i.e. 0.01)

- It is mainly important to have a temperature dependance of fc, ft and E, eps_cp, and of course eps_t,
  but the others can be left constant.

- It is important to use the total formulation with cca 20 steps

- It is also recommended to use the initial stiffness approach, i.e. elastic stiffness and calculation each step.

I hope my answers help and again sorry for late reply.

With best regards

Jan Cervenka

Quote Post 2