A multi-objective advanced design methodology dealing with seismic actions followed by fire on steel-concrete composite full strength joints with concrete filled tubes is presented in this paper. Instead of a traditional single-objective design where fire safety and seismic safety are achieved independently and the sequence of seismic and fire loadings are not taken into account, the new design approach should guarantee: i) seismic safety with regard to accidental actions; ii) fire safety with regard to accidental actions; iii) fire safety on a structure characterized by stiffness deterioration and strength degradation owing to seismic actions. In the seismic design of steel-concrete composite joints the component method was utilized, while the criteria of Eurocode 4 were exploited for fire design. In detail, these specimens were detailed in order to exhibit a favourable fire behaviour after a severe earthquake and designed according to Eurocode 3, 4 and Eurocode 8. The research activity was mainly concerned with the combined design of the proposed joints with concrete filled tubes together with the definition of some structural details for composite beams, such as the layout of structural steel reinforcements into the slab; and the definition of some details for the stud connectors around the column close the steel beam-to-column connection.In this paper the results of the experimental program on joints are described and the experimental results are discussed together with numerical simulation results on frames. The experimental activity demonstrated the adequacy of both the seismic design and performance of beam-to-column joints.
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