this article presents a risk-based methodology developed by Oxand, SimeoTM Ageing. This methodology aims at optimizing the maintenance of civil work structures. It ensures the realization of the whole maintenance process, going from the definition of maintenance targets (civil engineering components) and the related ageing risk factors to the realization and capitalization of maintenance actions through the computation of an optimized maintenance plan. This methodology is supported by a dedicated web tool which has been deployed, as an example, in the nuclear field.