Central lessons from the historical analysis of 24 reinforced-concrete structures in northern Spain

Since the late-nineteenth century, the use of reinforced-concrete as a structural material has proliferated and is now commonplace in the modern built environment. Some of the structures from that century are even considered cultural heritage. In the early stages of its technical development, concrete was seen as practically immutable over time; however, prolonged exposure to environmental agents has revealed its very significant problems of weakening strength and durability. A total of 24 aging reinforced-concrete structures in the Basque Country (northern Spain) and their behavior over time are analyzed in this paper. Reference is made to pathological reports, categorized for the purposes of this study, which characterize their concrete and steel components. This contribution greatly enhances our knowledge of each structure for future studies and for the improvement of their conservation strategies.