If we have some beams connecting to a perpendicular beam, should that perpendicular beam be split at the junction of the other beams or that beam can be merged into a single beam?
Forces between the beams (or other elements) in STAAD.Pro can be transferred only through the common nodes. If some beams do not intersect with other beam members, you need to split those beams in order to have common nodes with other beams, so that the forces could be transferred correctly.
You can quickly intersect members by selecting all members and going to Geometry -> Intersect Selected Members -> Intersect.