This work is a historical analysis of recent developments in structural design. It starts with the hypothesis that the search for efficiency and optimization of structures, undertaken with the birth of the Modern Era, continues to this day and has promoted, in the last sixty years, the emergence of a new level of complexity in geometry, design, calculation and construction of large-scale architectural projects. It also assumes that this search has as main objective the production of beautiful, rational and economic structures. Specifically, it analyzes how the search for efficiency and optimization of structures has recently evolved under the influence of new concepts emerged in the field of General Systems Theory, such as complexity, random, self-organization, indeterminism, emergency, nonlinearity and fractality. In recent research on the efficiency of architectural structures, a recurrent adoption of concepts such as self organization and fractality is observed through the development of structural ideas such as form finding methods, complex shapes adjusted to the physical stresses and models of fractal growth. In recent research on the optimization of architectural structures, considered as components that need to be coordinated on a building, it is possible to observe a trend towards the design of integrated devices capable of responding to multiple functions, to the hierarchical spatial coordination of architectural programs with hollows generated by the structure, and to algorithmic design.