Displacement capacity of reinforced concrete plane frames designed using the force- or ductility-based design approach

Capacity design of RC structures is the main approach adopted in all international seismic codes. It is mainly aimed at the optimal design of structural elements to maximize the dissipative capacity of the structure under seismic loads. The ductility approach seems to be the most appropriate to design seismic-resistant structures, however, both the Italian standards and EC8, for the latter only in low-seismicity areas, give the possibility to adopt an alternative design strategy in which all structural elements are designed to have a strength exceeding the seismic design demand. In this work, the displacement capacity of RC plane frames designed using the force-based approach and the same frames designed according to the capacity-design approach are investigated, showing that force-based designed structures can also have sufficient ductility to withstand seismic loads even greater than design loads.