Characterisation of vibration and damage in masonry structures: experimental and numerical analysis

For masonry structures, due to their heterogeneity and the complexity of the interface's behaviour between the blocks and mortar, the discrete element method (DEM) seems to be the best adapted to model this kind of structure, in particular for reproducing complex nonlinear post-elastic behaviour. However, unlike the software using the finite element method, the DEM does not directly obtain the natural frequencies and the mode shapes of the structure via a classic vibrational analysis. On one hand, these dynamic characteristics are needed for the structural design in the case of dynamic loads (seismic, impact). On the other hand, these dynamic characteristics can be useful for the assessment of existing structures by in situ dynamic tests. Therefore, the first objective of this study was to propose a technique that could indirectly identify dynamic characteristics of masonry structures using the DEM. The study began on a simple brick column structure. The sensitivity of the interface parameters following the dynamic characteristics was studied. Then, a masonry arch structure was studied. The technique proposed to identify the dynamic characteristics was validated by comparison with the experimental data. Based on vibrational analysis, the damage to the structure was assessed.