Shear Wall Design Inadequacy in ETABS

[meistersd]

I am designing an 8-storey RCC building in ETABS with lift core and shear walls. While designing for Shear Wall, I get the error message as indicated in the picture attached with this post. Currently, I have defined 250 mm thick wall section. However, the wall is failing in flexure and also some are overstressed in shear. Can somebody explain to me about these failures and how they can be corrected? Any link to reading about behaviour and design of shear walls in ETABS is also welcome!!

 

[Trenno]

Need more information... What's the pier size? strength? expected rebar?

But looking at your loads - you've got tension and major axis bending. Plotting the interaction diagram, your bending capacity is hindered once the section goes into tension. Your pier is also failing in shear.

Also, the fact that the top of the pier has more demand than the bottom flags up a potential error. Do you have a basement modelled?

 

[meistersd]

Yes. I do have a basement modelled. I have attached here the Shear Wall Design Summary generated from ETABS. Any help would be appreciated!

 

[Trenno]

The summary is a different set of loads to the original screenshot.

Anyway this pier isn't failing in flexure anymore but the boundary elements seem to be going over the limit (0.20*Fck). The pier is running at around 3MPa shear, which is quite high.

I suggest reading up on the backstay effect, especially in a seismic context. Few resources below.

Link 1

Link 2

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Link 8

 

[meistersd]

Thank you, @Trenno! I will go through them all!!