• Registered: 2014-02-17
  • Posts: 5

Topic: Tensile Strength of Material "3D Nonlinear Cementitious 2"

Hi there

I'm wondering which value to use as the tensile strength of the concrete in the ATENA 3D Engineering model for my experiment.  I am using "3D Nonlinear Cementitious 2" for the concrete material which has cube compressive strength of 44 MPa. The compressive strength is the average strength of six cube specimens with 150mm side dimensions.

The tensile strength that is assumed by ATENA for the 3D Nonlinear Cementitious 2 is 2.991 MPa which is based on the formula given in "ATENA Program Documentation Part 1: Theory" section 2.1.13.  But, the results that we are getting form the testing of concrete samples for tensile strength are different to 2.991 MPa.  We carried out six split test -indirect tensile test- on 100mm diameter by 200mm long cylinders which gave us the tensile strength of 2.1MPa. Further, we tested six concrete cylinders for “direct” tensile strength of the concrete which showed average tensile strength of 1.3MPa.  We tested the concrete samples at the age of 210days which was on the same week that we tested our experiment.

The question is which value would be the more appropriate value to use as the tensile strength of the concrete.  Is the tensile strength of material "3D Nonlinear Cementitious 2" refers to the “direct” tensile strength of the concrete derived from testing concrete samples?  Further, I would like to know what is the reference literature for the tensile strength formula in "ATENA Program Documentation Part 1: Theory" section 2.1.13?

Regards

Fariborz



*Please note I am aware of section 2.2.8 “How can I include the influence of shrinkage?” of ATENA Troubleshooting”

Quote Post 1

  • dpryl
  • CC software developer
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  • Registered: 2007-07-13
  • Posts: 1,107

Re: Tensile Strength of Material "3D Nonlinear Cementitious 2"

Hello,
yes, enter the tensile strength measured in the direct tension test into the material definition. As the difference between the default generated and measured ft is quite large, you should probably also adjust the fracture energy accordingly.

I would also suggest to model the splitting test and check if you reproduce the measured response, and adjust the material parameters if needed. You can do that with your direct tension test, too, if you feel you like/need it.

The most formulas come from CEB-FIP Model Code 90 (as referred in Theory 2.1.13), some from EuroCode 2, and also some other codes/code drafts. The tensile strength formula is one of the MC90 ones (note the code has the formula based on cylindrical strength, and the one in ATENA has been adjusted to take cube strength as the input).

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