As shown in some of the industrial buildings surveyed in the aftermath of the 2012 Emilia earthquakes, beamcolumn
and beam-joist interaction may imply a sort of unexpected restraint at the connection level due to the large relative rotation experienced, resulting in additional actions generally neglected in design (Fig. 2). Figure 3 illustrates the kinematics of this mechanism. Hence, the joints need to be designed and detailed to guarantee equilibrium under seismic action and relative displacement compatibility of the structural members, considering the concentration of strain and force demand at the connection level due to the greater flexibility of the connection compared with the connected precast concrete elements. This damage pattern and the related design aspects will be described in detail when discussing the experimental response of the two frames investigated.