Bassin 9

Dry Dock Seismic Analysis

The Arsenal of Brest is a military and naval facility located in the French town of Brest on the peninsula of Brittany in the Atlantic. In this installation, a large proportion of nuclear submarines of the French navy are based; for this reason, it is a sheltered and highly protected site.

The dry dock was built around the late 1990s and early 2000s and was originally calculated by SETEC engineering. The original concept included prestressed anchoring cables with the aim of maintaining stability in the event of an earthquake. A few years later, the strain in the cables were measured and it was found that a global loss of tension occurred in many of the cables.

Dynamis was in charge of reviewing the seismic stability of the dry docks, considering the losses in the prestressed anchors as input data. We diagnosed nonconformities in the seismic stability of the dry docks according to Eurocode 8. The inputs of this analysis were defined by the military authority based on different security levels.

Several scenarios were considered, among them the consideration of the dynamic effects of the sea (fluid-structure interaction) on the dry dock lock. The analysis we performed allowed us to find an optimal solution in which new, more effective anchors were proposed.

The analysis we performed allowed us to find an optimal solution in which new, more effective anchors were proposed.