Flat Slab Structural Response for Seismic European Design. Full Scale testing Results

The seismic design of flat slab frames is one of the topics needing code development in Europe. In fact, Eurocode 8 (2004) provides general indications for secondary systems bearing gravity loads coupled with primary seismic resistant members, but specific indications for flat slabs, which are typically considered as part of the secondary resistant system are missing. Furthermore, the Eurocode 8 draft (prEN 1998-1-2:2020) focuses on the design of flat slabs as primary systems. Test results in the literature for gravity and lateral loads include numerous tests on isolated slab-column connections. Only a few scaled-size flat slab frames and one full-scale experiment with North-American design for gravity loads have been studied; both cyclic loading and shaking table tests have been used. The SlabSTRESS (Slab STRuctural RESsponse for Seismic European Design) research programme was proposed to provide information on the response of a full-scale flat slab building and the basis for European code development. A new approach for the design of the specimen as a secondary structure was used, based on the analytical prediction of ultimate rotation capacity of the connections. The results show the response of the flat slab coupled with primary walls for seismic actions, and the full response to ultimate conditions for cyclic loading. Both the global and local behaviours are investigated, with and without shear reinforcement and different reinforcement details. A blind competition for the prediction of both the seismic and cyclic response was proposed to the scientific community, with the aim of exploring different options for modelling the response off flat slab frames.