Modelling of concrete swelling effects in dams, considering the influence of temperature, humidity, stress field, viscoelasticity and cracking

An integrated model, developed at the National Laboratory for Civil Engineering, to simulate the structural behaviour of dams affected by concrete swelling is presented. The model considers the influence of temperature, humidity, stress field, viscoelasticity and cracking. The concrete swelling model is based on concrete properties and temperature and humidity fields, and includes expansion anisotropy due to the stress state. The structural model considers the concrete viscoelastic behaviour and the cracking phenomena. The structural topology can be updated at any time to consider the construction sequence and modifications during the lifetime of the structure, while relevant actions are considered incrementally over time. The thermal and humidity fields can be modelled as diffusion processes. The simulation of dam behaviour is supported by a three-dimensional (3D) representation of the structure and its rock mass foundation, solved step-by-step by the finite-element method. Volumetric, joint and linear finite elements can be considered. A detailed 3D case study is presented, related to the analysis and interpretation of the structural behaviour of Covão do Meio arch dam in Portugal. The results from numerical analysis and continuous monitoring, including crack patterns, were in good agreement, attesting to the adequacy of the models and methods used to simulate the dam’s behaviour over time.