define confined concrete behavior
I was using total strain crack model with predefined compressive curve (THOREN) and lateral influence option (CNFCRV: VECCHI). However, compared with the increase of compressive strength, the increase of ultimate strain is very limited. The residual strength is also not presented. I tried with user defined curve but it can not work with the lateral influence option. Any idea will be appreciated.
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Dear Yihai,
It seems that you are using the correct syntax to include the confinement behavior of concrete in DIANA.
You complain about the limited increase of the ultimate strain for an increase of compressive strength. Do you refer to the ultimate compressive or tensile strain? To take into account the the lateral cracking effects, degration of concrete compressive strength due to cracking, you have to specify REDCRV with VC1993, see Section 6.2.5 of DIANA 9.4 Material Library manual for details. For the same level of loading, comparing with non-confined concrete response, if the compressive strength of concrete increases due to confinement, the strain field in the concrete body will decrease.
I hope it to be helpful,
Kesio Palacio
TNO DIANA support
Thank you Kesio. I am refering to the concrete ultimate compressive strain. I have some difficulty to understand the last sentence "For the same level of loading, comparing with non-confined concrete response, if the compressive strength of concrete increases due to confinement, the strain field in the concrete body will decrease." My understanding is confinement will not only increase compressive strength but also concrete ductility (ultimate strain, higher stress at ultimate strain). I am trying to validate FE model with experimental test, and I found softening behavior (post-peak) of simulated result shows sharper slope than test results which is caused by less-ducitile compressive softening behavior of concrete. I don't know if REDCRV option will change anything. Correct me if I am wrong. Appreciated for the timely reply to my question.