Leaderboard

Hinge at the top and pin at the top = pinned-pinned column. This might be the case for example in hollow core slab system. But even in that case, there is moment due to eccentricity of load. Yes you are right, building is unstable for lateral loads. BUT here in middle east which is not very active seismic region except boundaries at sea, 1.4D+1.7L combination governs instead of lateral combinations 90% of the times.

Yes Rana Waseem; The seismic load design is not required by municipality for this one story. But even though the point which I want to say is that the main designer neglected the moments at beam column connection that leads to a weak connection that doesn't resist any small moments coming from any lateral loads. This one story is composed of columns +beams + post tension slab only no shear walls.