Numerical model applied to the reassessment of the serviceability and safety of AAR-affected power-plant

Veytaux power-plant is a hydraulic facility affected by AAR. The concrete deformations of the structure are transmitted to sensitive equipments connected to it with major consequences on the serviceability and safety. Predicting the amplitude and rate of future displacements is an essential condition to choose the manager's strategy: adaptation of the equipment, repair or strengthening of the structure... The main difficulty lies in the heterogeneous moisture distribution which induces complex expansion gradients and the complex interactions between chemically-induced swelling and mechanical resistance of less-affected parts of the structure. Hence, the prediction of the displacement transmitted to the equipments requires a complete chemo-mechanical model of the structure. A macroscopic model is used and takes into account various coupling with moisture, temperature and stress states in the concrete. Its fitting requires several data: material samples from the structure for laboratory tests, monitoring devices for measuring displacements, moisture and temperature.... The resulting heterogeneous displacements in the concrete structure allow to re-assess the stress-state generated in the anchored equipment, especially in the 130-m long main distributor pipe.