Elementary concepts of structural robustness of bridges and viaducts

This paper will explain the elementary aspects related to structural robustness. The concept of structural integrity is firstly introduced and next it is considered how it varies in time. The different kind of progressive collapses are introduced with reference to real cases. Design strategies are then explained with reference of bridges and viaducts, considering examples. Finally, considerations about a more general view of structural robustness are enlightened. The role of design clima and conceptual design is stressed also in connection with structural health monitoring. In the whole paper, a practical point of view is used, as needed by designer.