Tracking modal parameters evolution of a school building during retrofitting works

During a seismic improvement intervention that lasted more than one year, a reinforced concrete (RC) school building had been surveyed through dynamic monitoring, granting continuous updates on its global response. Operational modal analysis was carried out to have a proper understanding of the structure's dynamic evolution, using a finite element model to perform a non-invasive and quantitative structural assessment taking into account the interactions with the surroundings. During the whole restoration works, the long-term (periodic) monitoring campaign showed the increment of the building performance remarked by the variation of natural frequencies. Also, the experimental assessment of the influence of infill masonry panels on the dynamics of RC frame is shown at each upgraded configuration. Additional restoration works, that may eventually occur, could benefit from the data collected during the present ambient vibration survey, providing useful parameters to enhance the retrofitting and the dynamic behavior of the structure.