ISSUE of FAReinforcedConcretePlaneStress material

[Zonghu Pei]

Dear STKO Team,

I am currently modeling a shear wall, but I encountered an error that says:

“FAFourSteelRCPlaneStress::FAFourSteelRCPlaneStress - failed to set appropriate materials tag: 21”

This occurs when I start the analysis. Could you please help me identify the cause of this error? I have attached the model file for your reference.

Thank you very much for your support.

Best regards,
Zonghu

[STKO Team]

Avoid using these materials; they give unrealistic results!

avoid_this.png (153.82 KiB) Viewed 243 times

There is also a note on the documentation:
https://opensees.berkeley.edu/wiki/inde ... _Materials

Please follow our webinar on modeling shear walls with shell elements and the new ASDConcrete3D material:
https://asdea.eu/software/advanced-e-learning-courses/
#032 ASDConcrete3D: A new 3D constitutive model for concrete and masonry-like materials

[Zonghu Pei]

Dear STKO Team,

I have followed your advice to model the shear wall using shell elements, and the analysis runs successfully. However, I’ve encountered an issue: the reversed axial load seems to have no real effect on the shear wall response. Specifically, I expected the structure to exhibit different hysteretic behaviors in the positive and negative directions, but the hysteretic curves are nearly symmetrical.

Could you please help me identify what might be wrong with my model?

Many thanks for your support and guidance.

Best regards,
Zonghu

[STKO Team]

If you monitor the vertical reaction force at the base, you will see they are not being imposed as you expect.

When you do a Displacement Controlled analysis, all loads imposed for that analysis (in your case both the vertical and the horizontal) will be controlled by the displacement-control analysis (where the lambda = time step = load multiplier). And those load MUST have a linear time series (so that time step = lambda).

Since you want only the horizontal force to be displacement-controlled, while the axial force should be load-controlled (according to your time-series), you should do an indirect-displacement-control analysis:

• Define the vertical action as a load + the associated time series (exactly as you did)
• Define the orizontal action as an imposed displacement (load -> sp) + associated displacement time series
• Create a load patter for each one
• Do a Load Control analysis, where the duration is equal to the duration of your time series