Seismic design of innovative steel frames with partially‐prefabricated infill walls

Hybrid steel and concrete seismic-resistant systems made by steel frames with reinforced concrete infill walls (SRCWs) have potential advantages over structural solutions made only by steel or reinforced concrete (RC). In fact, the high initial stiffness of concrete is useful to minimize the damage of non-structural elements under frequent (low to moderate) earth-quakes while the ductility and dissipative capacity of the steel allow good performances under rare (high-intensity) events. Eurocode 8 considers SRCW systems to behave essentially as RC walls. However, numerical analyses on SRCWs, designed according to the Eurocodes, pointed out an unsatisfactory seismic behaviour with discrepancies between the behaviour assumed in the design and the simulated response under seismic actions. Indeed, the idea of stiffening a steel frame with a RC infill leads complex mechanisms that are difficult to control as being affected by many variables. In this study, some of the recent developments made for innovative SRCW are transferred to hybrid steel and concrete walls with partially-prefabricated infills. Numerical models are analysed to understand the global behaviour of the considered SRCWs and to provide a preliminary validation of the proposed structural solution.