Concrete swelling: Studies and pragmatic results. Case study of Cleuson dam

Concrete swelling affects most of the existing concrete dams in Switzerland. The peculiar case study of the Cleuson dam, a 87 m hollow gravity dam, is proposed. Irreversible movements of the dam body have been measured almost since the first impoundment and significant cracking in the upper part of the structure has been monitored since 2005. Based on the observation of the cracking and preliminary calculations, an operating restriction of 2 m was decided in 2008. In 2012, further investigations led to characterization of the cracking and determination of the concrete pathology. On this basis, a finite element model was made in 2013, implementing the movements, the cracks and the concrete swelling. The results showed that the structural safety was guaranteed. In view of the dam body swelling pursuit, new studies were carried out in 2021 and 2022 to estimate the time frame in which the safety of the structure would no longer be guaranteed. Analyses of the probable failure mechanism associated with a damage model showed that a risk of failure should not appear before 30 years.