Surrounded by the Alps, the Jura and Lake Geneva, CERN is located in a particularly complex geological setting, which also happens to be a non-negligible earthquake-prone region. Compared to the rest of Europe, Switzerland has a moderate seismic risk, but the Swiss Seismological Service (SED) indicates that earthquake activity is not evenly distributed throughout the country: the Valais region is the most prone, followed by Basel and Geneva.
To gain a better understanding of the seismic risk, CERN has, since 2021, been running dynamic seismic analyses on some of the concrete blocks used to shield people from ionising radiation in most of the experimental areas, in order to be able to predict the mechanical behaviour of this type of structure.
Current regulations in matters of seismic risk cover ordinary buildings, but not complex research facilities like those of CERN. Further, shielding block configurations are not covered by European or Swiss norms. In the light of this gap, and in order to provide a means for CERN to assess seismic activity in relation to such configurations, a project was set up to develop an ad hoc assessment methodology compatible with the criteria for seismic safety in the Host States.
This project is being led jointly by Luca Sironi (SCE-SAM-TG) and Marco Andreini (HSE-OHS-IB), alongside the Beams department. Other renowned institutes, such as the California Institute of Technology (Caltech), the Swiss Federal Institute of Technology Lausanne (EPFL), the University of Montpellier and the European Centre for Training and Research in Earthquake Engineering (EUCENTRE), are also participating.
A report on the proposed assessment methodology for typical CERN shielding block configurations will soon be presented to the management of the SCE department and the HSE unit. The objective is to integrate this methodology into routine operations, including the conceptual design of new facilities and the consolidation of existing ones. Having calibrated the open-source software LMGC-90 (developed by the University of Montpellier) in 2021 based on experimental results collected in 2019 at EUCENTRE (Pavia-Italy), CERN is now further refining its seismic safety assessment methodology, based on incremental dynamic analysis, in the spirit of the continuous improvement of safety at the Laboratory. The main objective is to run this analysis on real block configurations at the beginning of 2023.
Until now, studies have been mainly theoretical and have lacked the support of experimental tests. This work has now not only been validated by experimentation, but can be used routinely from now on, representing a new competency at CERN. The Seismic Safety Project will now enter its next phase of development, with some case studies in the pipeline. Luca and Marco underline the potential of this research: “Thanks to the collaboration between institutions, it has been possible to work at the forefront of the research in matters of seismic safety. The research findings can be extended to similar structural typologies for other laboratories around the world.”
Find out more about the project on this poster (sign-in required).