Concrete Frame Design

I am designing a concrete pan joist floor to take the seismic shear. It's a concrete frame with pan joist connected to east-west beams between columns.
How would I model the 2D frame in StaadPro? Should I model the stiffness of the two neighbouring joist connected to columns and apply lateral loads to it?
Please advise.
Thanks in advance.

 

[JAE]

If you model the adjacent joists, you must ensure adequate torsional stiffness and strength in the supporting beams as the adjacent joist moments must be transferred into the columns for frame action to work.

Typically, on pan joist construction, we would create a wider (and perhaps deeper) joist on the column line to create a true beam-column system in both directions.

Also remember that if you count on the three adjacent joists for lateral resistance, their stiffness cannot be modeled by just adding their individual Ie values. This is because two of the joists would not frame directly into the column, but depend on torsional rigidity of the supporting beam.

Finally, a pan joists is typically a thin webbed member. With lateral loads you will most likely have compressive forces in your longitudinal reinforcing. This will require ties around the longitudinal rebar to confine and ties are not easily provided in thin webbed joists.

 

[lutein]

Thanks for the help. After reading your advice regarding torsional stiffness of the beam to transfer the shear, I have decided to run a detail 3D analysis on a critical frame and get the beam designed for the induced torsion.
Thanks