Seismic Analysis for building

Hello,

Thank you for waiting us !
I've checked your model file, and found that the nodes(footing member and the 1F plates) are not shared each other on the first floor.
And the supports does not resist for the rotation, so the stiffness of footing member was almost 0. Please change the support and mesh the 1F plate like the below image.

Thank you.

Best regards,
Jihong Hwang

Dear JiHong,

From the diagram you showed, is to change the pinned support to fixed support but my design of my bottom support is pinned support, if change to fixed support may have moment which my foundation is not design to resist the moment. Is it this is the only way to solve the problem for the seismic analysis?

Hello,

Thank you for waiting us!
It is okay to use pinned support in your model. Just change the mesh on the 1F plate to share the nodes with the footing member.
Thank you.

Best regards,
Jihong Hwang