Cracking in Shell Elements

[BSchwab]

I'm trying to model a tilt-up panel with an opening in the middle. I am using the layered shell elements to account for both the axial force and the out of plane bending. The results seem to be good for a linear elastic analysis. However, when I switch to nonlinear analysis, the effects of concrete cracking do not appear to be taken into account. This is critical for my design because without cracking, the deflection is reduced, and the subsequent P-delta effect is not properly accounted for. I have tried adjusting the stiffness modifiers but those seem to have no effect. In addition, it seems like there should be an automatic way to make SAP2000 calculate this.

Am I going about this in the proper way? Or am I just missing some little button? I would appreciate any help in this matter.

Thanks,
Brandon

 

[vaquers]

Dear Brandon,
when I want to take into account the cracking in concrete I use the property modifiers (according with ACI 318-08, Section 10.10.4.1) with the p-delta method. Personally I believe this is the correct way to model this kind of problem. Are you sure that you are running the nonlinear case propertly? Regards,

Sebastian