Spur dikes—in various forms such as solid or hollow gravity (buttress or arch with vaults or slabs)—are a type of structure that is largely abandoned internationally, although there are some relatively recent examples from the 1970s-1980s (e.g., Haen Dam, 1963 and Storfoss Dam, 1982, in Norway). In Italy, there are numerous examples of this type of structure built between the two World Wars or immediately after the war.

In Italy, there are a total of 37 spur dikes (40% solid spurs, 30% lightened gravity, 30% vaults/slabs and buttresses or similar).

The issues with these structures are well-known: cracking (generally caused by thermal phenomena, leg instability, expansive chemical reactions, etc.), degradation associated with environmental conditions (e.g., corrosion of reinforcements when present), aging and degradation due to constituent materials. In addition to these problems, there are some critical issues related to compliance with the recently revised regulations, which require verification of conditions not foreseen during the design phase (e.g., seismic loads or updated criteria on evaluating subpressures).

The assessment of these structures has highlighted the need to systematize knowledge of the phenomena that have led to the aforementioned problems, to deepen the evolutionary dynamics of decay and cracking states, and to share experiences on rehabilitation interventions. Numerical modeling has certainly contributed significantly to understanding these phenomena and evaluating structural behavior under applied actions. Some of the aforementioned issues have been topics of benchmarks proposed by the ICOLD Technical Committee “Computational Aspects of Analysis and Design of Dams”.