Dynamic identification of a masonry structure through a MEMS based monitoring system

The number of applications of structural health monitoring techniques to buildings is steadily increasing, fostered by the diffusion of low-cost accelerometric sensors based on MEMS. In many cases, these sensors may represent an alternative to more expensive transducers, such as piezoelectric accelerometers, even if they typically have lower signal-to-noise ratios. Their higher noise levels may limit the capacity to identify modal parameters of structures when small amplitude vibrations are recorded. The present paper presents the results of an experimental campaign in which two SHM systems were installed on a masonry building built at the CIRI Buildings and construction Laboratory of the The University of Bologna, recording accelerations for more than six months. One system was based on uniaxial piezoelectric accelerometers, and the other on triaxial MEMS. The data recorded by the two systems were used as input for output-only structural identification algorithms. Using the results obtained from the piezoelectric accelerometers as the reference, the capacity to identify the modal features of the building from the MEMS data is analysed.