Topic: Cyclic Modeling of Low Rise Shear Walls in ATENA 2D
I am currently matching the experimental results for four low rise walls (aspect ratio between 0.5 and 0.75) which were tested reverse cyclically using the ATENA 2D software.
Steel: Discrete rebar, Multi-linear Cyclic Reinforcement
Currently, the models, when analyzed monotonically, provide accurate predictions for the backbone curves as compared to the cyclic experimental results and reasonable predictions of cracking damage and peak lateral strength. When trying to use the same material properties defined in the monotonic analyses in cyclic models, I am having issues with the models having reduced damaged stiffness and they are unable to run to the drifts reached during the experiments. From my analysis of the failure of the models, it seems that the first row of concrete elements has significantly localized damage from the cycling, resulting in lower minimum principle compression stresses as seen in the monotonic models, resulting in this reduced damaged stiffness and premature specimen failure.
Are there any concrete material parameters that would help with the cyclic behavior of this concrete material model?
Would using the 3D analyses in ATENA Science solve any of these issues, or would it be better to get improved behavior in the 2D analyses?
Would incorporating an interface help this behavior? In the tests, the interface was a cold joint, which had observed gap opening early in the test and low slip until peak load. Is there documentation on properly defining the cohesion, tensile strength, and coefficient of friction, for a model like this, where gap opening is important to the behavior and slip should not reduce the peak load behavior?
Thanks for any assistance, I can also provide more detail on my concrete and rebar models and variations I have tried to improve the cyclic behavior.