Durability analysis of the maritime infrastructure for the Monaco Sea extension

The construction of an artificial peninsula extending the Monaco territory is destined to create an urban area of 6 ha. The preliminary works started end 2016, with the full completion of the maritime infrastructure by the end of 2020 and the delivery of the first buildings from 2022. The project requires the prefabrication of 18 caissons, which will constitute the maritime infrastructure of the extension at sea. Located at Marseille (200 km away from Monaco), the prefabrication of the caissons has been carried out by means of a floating structure (“caissonnier”) measuring 56 m long, 50 m wide, and 27 m high. During to the construction process, the caissons' rafts and the walls will be exposed to chlorides at early ages (5 days for rafts and 3 days for walls). The client's requirement was to implement a performance‐based durability design approach for all the concrete works of the maritime infrastructure. This approach implies to justify a 100‐years lifetime. The paper presents the methodology used to deploy a performance‐based design approach on this project. In particular, it details how the durability criteria have been set up in connection with the fib Bulletin 34 probabilistic models in order to target the 100‐years lifetime, but also the provisions (increased concrete cover, protective coating) for controlling chloride ingress at early age. In addition, the paper provides special attention in order to explain how the durability criteria are checked during the concrete production phase by the work site and the ready‐mix supplier.