Ram concrete tall building modeling 1

[strguy11]

I'm new to ram structural system. For a tall building of 16 stories (concrete columns, pt flat slab,concrete shesrwalls), i have a question about the modeling of the lateral system. When looking at the columns, do you model then as lateral columns as well as the shearwalls? I have run models both ways and the lateral drift is significantly different (less with kayak columns).

It seems like kayak columns would be correct because I'm not sure that they would act as pinned. Would this then be to be classified as a dual system in asce 7-10, or can it be still a shearwall system??

 

[BulbTheBuilder]

Depending on the framing, you can ignore the columns and let the shear wall take all the lateral loads. Even if the framing permits this, watch out for columns around the shear wall as they will attract some lateral forces. This means modelling the columns as gravity only and possibly increasing the thickness of the wall for drift or strength.

ASCE 7-16 12.2.5.1 states for dual system, the moment frame should be capable of resisting at least a quarter of the seismic force. Some also use ACI 318-19, 6.6.4.3 to check if they can analyze columns as non-sway or sway.

Your forces might also contribute to your design system. If you are located in a region with higher lateral forces, then I will consider the columns taking some lateral loads to be on safe end with my column design.