Suspended Shear Wall - To Avoid Underpinning - Plausible?

[bdtoktay]

Hi all, to anyone with extensive shear wall design experience,

What would be your plausibility opinion on the attached suspended shear wall concept from a 10 story CIP structure?

The goal is to avoid underpinning of adjacent building and SOE. The shear walls near lot lines would extend as normal from the roof to 1st floor, but then they would rotate to a 45 degree angle, following the permittable excavation line, and meet the foundation about 10 ft away from the lot line.

Your opinions are appreciated! Cheers.

 

[HTURKAK]

IMO , it is not reasonable to support 10 storey shear wall on the 10 ft cantilever extension of the basement . The vertical structural irregularity is also prohibited or limited acc. to SDC .( refer to applicable seismic code in your region).

I will strongly recommend to extend the shear wall to the foundation level. You may use soil excavation support or prefer underpinning of the adjacent structures.

 

[structSU10]

I agree - avoid this. Maybe move the shearwall inboard away from the lot line and lose that section of basement you currently show as the cantilever?

 

[bdtoktay]

Thank you for the response, HTURKAK and structSU10! This option is definitely avoided. Shear wall is now extending down to foundations.

 

[MotorCity]

I don't like it either. Might be onboard if it was 1 or 2 stories but not 10. Even it could work, it'd be a nightmare to form.
Maybe look at a mat foundation or grade beam system on drilled piers.