Seismic engineering is constantly looking for new strategies and methods that provide designers with the opportunity to get more and more efficient solutions both from the performance and from the economic point of view. In this context, the scientific community is called not to miss its support and to face the new challenges coming from the observation of the damage caused by the recent earthquakes. This Special Issue of “Ingegneria Sismica” collects some works focusing the theme of the seismic vulnerability, some of them specifically refer to mitigation strategies while others address modeling strategies. Obviously, for the multiplicity of aspects involving the theme of “seismic vulnerability”, only a few issues have been discussed. In particular, some works deal with the theme of base isolation from the point of view of design and seismic reliability, others are focused on the theme of structural robustness considered as a further goal of seismic design. Further papers are deepening the problems of interaction between frames and masonry infills, providing simplified modeling strategies, suggesting criteria to reduce interaction effects, but above all by providing methods for the analysis of combined in-plane / out-of-plane behavior. The themes related to modeling are also addressed with particular care. Other papers in fact face the issues of model uncertainty and of the reliability of constitutive laws for normal and high strength confined concrete, being the latter of fundamental importance for the assessment of the rotational capacity of reinforced concrete structural elements under seismic actions. Moreover, the problem of the reliability of seismic vulnerability assessment methods is also discussed, with particular reference to multimodal “pushover” analysis. This Special Issues is composed of 10 paper produced by 29 authors, to whom we would like to address a special thank for the effort made during the editorial phases. Finally, the Guest Editors, Paolo Castaldo, Liborio Cavaleri e Fabio Di Trapani, wish to thank Prof. Gianmario Benzoni and Prof. Rosario Montuori for this opportunity and for their assistance.
