Steel gates are an essential component of any hydroelectric plant and their safety is essential for the correct functioning of these systems. In most European countries, where the development of hydroelectric power plants began in the early 1900s, the problem of aging infrastructure, including penstocks, is a common element. In addition to this aspect, the risk assessment of these infrastructures must be reconsidered because the case of plants built in areas without human settlements which have since been progressively developed is quite common.

In some cases, to these more general aspects must be added the critical infrastructural issues caused by geological-geotechnical phenomena that were not identified in the design and construction phase. This is the case of the Perrères steel penstock, located in the Aosta Valley, built in the 1940s on a slope where a deep-seated gravitational slope deformation (DsGSD) was later found. The penstock required several structural rehabilitation interventions. Recently, CVA, owner of the plant, started an intense monitoring campaign with the installation of integrated systems to detect changes in ongoing phenomena and to monitor the behavior of the structure. At the same time, CVA entrusted RSE with the task of developing a highly detailed finite element model for evaluating the current stress-deformation state of the system. Based on the measurements provided by the monitoring system and the possible evolutionary scenarios of the GDPV, this numerical model will determine the behavior of the pipeline and identify possible rehabilitation interventions to guarantee the long-term safety of the infrastructure.