Interest in designing structures that cost less to repair after they have been subjected to strong earthquakes has been increasing in the recent years, which led to the development of innovative repairable welded FUSEIS beam splices serving as dissipative beam-to-column connections in moment resisting composite steel and concrete frames. Upon a review on the individual characteristics of the beam splices obtained from an extensive experimental campaign, retrieving the necessary information to perform their modelling and validation in numerical analyses, the beam splices were applied on 3 case study building configurations comprising of 2, 4 and 8 stories to evaluate their global performance under seismic action. Numerical analyses were performed, in which the buildings were designed and safety checked through a Eurocode 8 based procedure that had been proposed herein, including Linear Response Spectrum and Non-linear Static Pushover analyses. Comparison to equivalent traditional moment-resisting frame structures was conducted as well. The outcomes of these numerical analyses were satisfactory: (i) the system exhibited good behavior under seismic action, proving to be relatively strong and stiff with large capacity of energy absorption and (ii) inelastic deformations were strictly limited to the beam splices, avoiding the spread of plasticity to the rest of the structural elements.