[en] The first objective of this research thesis is to provide, by using assessment techniques, a time series of bi-dimensional mechanical statuses of a nuclear reactor enclosure, based on measured data and available data related to mechanical and climatic loads, and by taking into account information from the model and data uncertainty. A second objective is to determine a general mechanical model allowing predictions regarding the future mechanical status from various loading scenarios or climatic loads (long dryness periods), including scenarios of structure repair or modification