Seismic assessment and retrofitting of a public building

Aquathermal center of Eaux-Bonnes, France
Seismic study of the existing structure of the rehabilitation project of the aquathermal center of Eaux-Bonnes, France. Mixed structure : reinforced concrete and stone masonry for the existing, timber for the expansion. Seismic assessment, retrofitting solutions, and final calculation check.
Grontmij asked NECS to carry out a technical study on the rehabilitation and expansion project of the aquathermal center of Eaux-Bonnes. The project aims at redevelopping the existing therms and expanding the structure by adding several levels on top of the central part of the existing building.

The aim of the study was principaly to verify that the project was satisfactory with regards to the 22/10/2010 Ministerial Order for existing structures, and to check the seismic behaviour of the future building in the project configuration.

The study was divided into several steps. The first step involved a first analytical analysis and gave an expert point of view regarding the consequences of the structural modifications on the building seismic behaviour. The second step involved a more detailed analysis based on numerical modelling and calculations (modal-spectral analysis). The goal of that second step was to give the complete demonstration of the structural consequences of the expansion on the existing building. Finally, the third step aimed at providing retrofitting solutions and carrying out a final calculation check.