Concrete Tank Wall - Varying Thickness - STAAD Analysis

[Jacst3]

I’m analyzing a concrete tank wall, which will have different thicknesses as the wall height increases. The inside face of the wall will always be at the same plane, where as the exterior plane of the wall will “step” inward to reduce thickness.

Modeling in STAAD with plate elements, the differing sections are aligned along a common center line. How can I model the wall to keep the interior face of each section on the same plane? I imagine that I model the wall offsetting the differing sections based on actual eccentricity, and then connect those joints as master and slave. Here each section of differing thickness will be arranged in the correct location in space, but they will be rigidly connected. Is this a proper modeling assumption and is the resulting stress distribution accurate to real-life?

Or - does this even matter? Will I get the same "real-life" results if I analyze the wall as if the sections were "stacked" along their respective centerlines?

Attached is a screen shot of the two options.

Thank you for any input.

 

[KootK]

Or - does this even matter? Will I get the same "real-life" results if I analyze the wall as if the sections were "stacked" along their respective centerlines?

I don't think it matters. I might even prefer the model with the walls centred. Simpler modelling usually makes me feel more confident about the results.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.