Vol.:(0123456789) Bulletin of Earthquake Engineering (2019) 17:1029–1052 https://doi.org/10.1007/s10518-018-0483-9 1 3 ORIGINAL RESEARCH Tracking modal parameters evolution of a school building during retroftting works Alessio Pierdicca 1  · Francesco Clementi 2  · Andrea Fortunati 1  · Stefano Lenci 2 Received: 21 May 2018 / Accepted: 24 September 2018 / Published online: 27 September 2018 © Springer Nature B.V. 2018 Abstract 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 fnite 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 infuence of infll masonry panels on the dynamics of RC frame is shown at each upgraded confguration. Additional restoration works, that may eventually occur, could beneft from the data collected during the present ambient vibration survey, providing useful parameters to enhance the retroftting and the dynamic behavior of the structure. Keywords Ambient vibration survey · Dynamic identifcation · Retroftting works · Dynamic calibration · Infll panels Abbreviations AV Ambient vibration AVS Ambient vibration survey RC Reinforced concrete NM Numerical model IEPE Integrated electronic piezoelectric SPS Samples per second SSI Stochastic subspace identifcation * Francesco Clementi francesco.clementi@univpm.it 1 DRC – Diagnostic Research Company, Via Montesicuro, 60131 Ancona, Italy 2 Department of Civil and Building Engineering and Architecture, Polytechnic University of Marche, Via Brecce Bianche 12, 60131 Ancona, Italy