Lock gates, pipelines, valves, turbines, and reservoirs: many types of hydromechanical equipment rely on metal structures that are subjected to repeated stresses over time. As infrastructure ages, these stresses can contribute to the development of fatigue, which may compromise the reliability and safety of these structures.
In the water, energy, and civil engineering sectors, much of the infrastructure built after World War II has now been in operation for several decades. As a result, managers face a major challenge: better anticipating the remaining service life of these structures in order to adapt their maintenance, monitoring, and replacement strategies.
This thesis project is part of the Medelia Chair’s mission: to develop advanced scientific methods to improve the durability, safety, and performance of metal hydromechanical structures.
Video Testimonial: Kamal Harb, Ph.D. student at the Medelia Chair
The scientific quality and clarity of presentation of Kamal Harb ’s work were recognized at the HydroES 2025 conference, where he won the “My Thesis in 180 Seconds” award. This recognition highlights the significance of his research and underscores the doctoral student’s ability to make complex scientific topics accessible to a non-specialist audience.
Project objective
This dissertation aims to develop a methodology for probabilistic fatigue analysis applied to mechanically welded steel structures, particularly the hydromechanical components of dam gates.
The goal is to provide infrastructure managers with more reliable tools for assessing the remaining service life of structures. These tools should make it possible to better characterize fatigue-related damage, account for uncertainties related to materials, loads, geometry, or construction quality, and inform maintenance decisions.
An approach based on fracture mechanics and probabilistic modeling
The research is based on an approach that combines fracture mechanics, probabilistic fatigue analysis, and stochastic finite element methods.
The research focuses specifically on aging mechanically welded structures, for which there are numerous uncertainties: operating conditions, material variability, joint geometry, weld quality, and stresses induced by vibrations, hydrodynamic effects, or changes in operating conditions.
By incorporating these various sources of uncertainty, the project aims to better predict the progression of damage and provide a probabilistic assessment of the structures’ remaining service life. This approach paves the way for more robust decision-support tools for operators and managers of hydraulic structures.
Expected Impacts
For the industry
- Improving the assessment of the remaining service life of hydromechanical structures.
- Provide decision-support tools to guide maintenance scenarios.
- Take better account of uncertainties related to materials, loads, and operating conditions.
- Contribute to the fatigue analysis of aging metal structures.
- Support managers in monitoring and prioritizing interventions on critical infrastructure.
For the society
- Enhance the safety of water and energy infrastructure.
- Extend the useful life of existing infrastructure.
- Minimize premature replacement of heavy equipment.
- To contribute to a more sustainable and responsible management of industrial heritage.
- Help ensure the continued reliability of structures essential to energy production, navigation, or water management.
Research conducted in close collaboration with stakeholders in the field
The project is being carried out with the support of several major industry partners:
These collaborations help ground research in the practical challenges faced by managers and operators of steel infrastructure. The results thus aim to address real-world issues related to monitoring, maintenance, and decision support.
The Team Involved
Thesis Advisor:
- Rafael Estevez, director
- Julien Baroth, co-director
Industrial supervision (SPRETEC, Artelia Group):
Ph.D. student:
“These welded steel structures perform essential functions. Gaining a better understanding of how they degrade means preserving a strategic asset and ensuring the long-term reliability of our infrastructure.”
Planification
Thesis defense tentatively scheduled for November
