Seismic Fragility Assessment of the SHiP Decay Vessel

SHiP Experiment aims at exploring the Hidden Particles sector. The decay vessel is a long structural steel hollow structure allowing the hidden particles to decay into Standard Model elementary particles to be detected. This very massive structure is expected to lay on the floor in a possible future underground facility at CERN, where the seismic activity is non-negligible. The dynamic analysis of the SHiP decay vessel is then an important step in the structural assessment of this part of the detector. As part of the SHiP collaboration activity, the seismic assessment of the SHiP decay vessel is conducted in order to give important recommendation for the geometrical and structural design of this structure. Thanks to Finite Elements and Response Spectrum analyses and through mechanical and programming software applications, an equivalent static analysis allowed to predict the seismic behaviour of such a vessel. The seismic assessment is mostly done by using probabilistic approach and plotting the structure fragility curves representing the probability of exceeding a certain limit state at a given earthquake intensity measure, in particular the Peak Ground Acceleration.