The vertical stability of a slender precast concrete system has been studied theoretically. The
system has bearing façades composed of composite columns and deep spandrel beams. Floor
elements are connected to the spandrel beams by tie arrangements. A theoretical model of the
interaction between load-bearing floors, beams and columns is presented. Floor-beam-column
subframes that have been tested experimentally have been analysed. The agreement between
measured and calculated responses was good. The structural system in a building was analysed
for several situations, both ordinary and accidental. It was found that the action of the beamfloor
connections increased the torsional moment in the spandrel beams in all of the ordinary
load cases studied. The analyses of the behaviour in accidental situations showed that the beamfloor
connections used nowadays have too little deformability. As a consequence, in an accident
the floor elements would fall down onto the floor below which probably could not resist such
impact loading; the connections would probably not be able to prevent a severe collapse in
accidental situations
