When correctly connected to the masonry walls, the composite floor (wood, steel, or hollow bricks and concrete) is the ideal solution for seismic adaptation, in addition to ensuring sufficient base rigidity, particularly in case of recovery of existing structures (see section 220.127.116.11 in EN 1998-1-1 – Eurocode 8).
The Eurocode 8 EN-1998 -1-1 provides indications for the verification for buildings subject to seismic action.
Extract from 18.104.22.168 Diaphragmatic behaviour at storey level:
(1) In buildings, floors (including the roof) play a very important role in the overall seismic behaviour of the structure. They act as horizontal diaphragms that collect and transmit the inertia forces to the vertical structural systems and ensure that those systems act together in resisting the horizontal seismic action…..
(2) Floor systems and the roof should be provided with in-plane stiffness and resistance and with effective connection to the vertical structural systems…..
(3) Diaphragms should have sufficient in-plane stiffness for the distribution of horizontal inertia forces to the vertical structural systems…
A video shows in simple terms the concept of “box action“.