Cervenka Consulting Forums — Confined concrete in ATENA 2D

Re: Confined concrete in ATENA 2D

2011-11-18T12:04:32Z

You can try it, but do not forget that plane strain means the strains in the 3rd directions are zero, which can lead to compressive or tensile stresses depending on the specific setup and location, mainly governed by the Poisson's ratio (mu). The plane stress model is typically used when the dimension in the 3rd direction is large, e.g., a long pipe or tunnel.

Re: Confined concrete in ATENA 2D

2011-11-15T08:39:55Z

Yes, send the model along with some sketches and/or photos of the experimental setup.

Re: Confined concrete in ATENA 2D

2011-11-14T14:59:46Z

No, the boundaries, geometry and the mean values are ok. Also the reinforcement amount is checked. In experiment we tested r/c frame on which axial load on columns is applied, but the supports allowed movement of column tops only in horizontal direction while the base beam reamains fixed. Than we applied horizontal force i.e. earthquake load. No movement of the steel bam that prevents vertical displacement upward is noticed. I can send you my model if it will help.

Thank you!

Re: Confined concrete in ATENA 2D

2011-11-14T12:58:24Z

If the calculated initial stiffness differs from the measured, the things to check first are 1. the elastic modulus and 2. the geometry and boundary conditions.
Ad 1: When using the EC2 generator, are you sure you are using the Mean values (i.e., not design)?
Ad 2: Typical problem sources are wrong thickness or supports model.

Re: Confined concrete in ATENA 2D

2011-11-14T11:16:12Z

I have found in ATENA theory that the CC3DNonLinCementitious2 will include confinement, and it has been proven very good since for the same "plain" concrete strength i have results more similar to the experiments, than for other concrete model. Problem is that its not really enough i.e. i need more force at given displacement, so it seems that i will have to use 3D model. Please tell me what you think about everything.

Confined concrete in ATENA 2D

2011-11-14T08:48:42Z

Through model of R / C elements in 2D ATENA i have failed to get a good agreement with experiment, where i have used as initial data the experimental results on constituens (concrete cube strength). Although I noticed that I need to use the initial modulus of elasticity rather than secant, it was not enough to achieve the same slope of the force in relation to the displacement. Curve that I have obtained by calculation is still much weaker. So I tried to change the parameters of the concrete as it is the case of confined concrete, because of the influence and the amount of transverse reinforcement. I wonder if ATENA2D itself has already taken the effect of confined concrete into account. Since I have very good experimental data about the reinforcement properties is it possible that on any other way to increase the initial stiffness of the model and have a good physical explanation. Please explain me about confined concrete.

P.S. I have used EC2 formulas for confined concrete (page 36) but still in my model there is not enough initial stiffness, since probably because confined concrete affects strength and deformation, but other parameters remain unchanged (elastic modulus).
Kind regards and thank you for your support