To prevent transferring moments of the ceiling structure on the downstand beam, you can define "scissors releases" when using ceiling beams. In order to consider the same effect in the case of a flat ceiling (for example, cross‑laminated timber), you can use the "Line Release" option. Using this function, you can "release" the φx degree of freedom, whereby the downstand beam is connected rigidly around the local x‑axis to the surface. This way, you can represent the continuous effect of the surface very easily (without using coupling members).
The second part of this post will describe a semi‑rigid shear coupling between the surface and the downstand beam according to American standard ANSI/AWC NDS and Eurocode 5.