This monograph focuses on an eminently practical issue, which allows to take advantage of the characteristics associated with high ductility steels: the confinement of concrete. An adequate disposition, not only of the transversal reinforcement, but also of the longitudinal reinforcement itself, can considerably increase the performance of the structures. This fact is something fundamental when the structures are subjected to actions close to the collapse situations, as it happens in the case of some earthquakes. Given the importance of this last aspect, as well as the increasing importance that issues related to the earthquake are beginning to have in Spain, this monograph analyzes which are the most appropriate structural typologies in these situations, and what is the contribution of high ductility steel to the improvement of its behavior. The result does not shows excessive surprises. The structurally "more robust" typologies are those constituted by moment resisting frames, consisting of a network of beams and columns. Other typologies, commonly used in our country, such as the structures with columns and slabs, or with flat beams, remain on the side of insecurity. The contribution of high ductility steels is very favorable in the case of the appropriate typologies, while it is insufficient to resolve the bad seismic behaviour of the "more sensitive" typologies.