GNGTS 2015 - Atti del 34° Convegno Nazionale

230 GNGTS 2015 S essione 2.3 Conclusions. In the paper, dynamic characterization of the cable-stayed bridge of Pietratagliata was carried out using ambient vibration tests and FE analyses. A refined 3D FE model of the bridge was calibrated (FE-OPT), based on natural frequencies and modal shapes extracted from FRFs, as well as dynamic measurements of the axial forces on the cables. The optimized 3D model highlighted the importance of geometrical refinement and computationally expensive but accuratemodelling assumptions, and resulted in good agreementwith experimental predictions, hence suggesting its use as a baseline for further diagnostic investigations and monitoring programs. The sensitivity of the bridge dynamic parameters to damage in the cables, specifically, was properly assessed by means of extended numerical studies (FE-DAM). The main effects of damage on natural frequencies, mode shapes and axial force on the undamaged cables was emphasized. Acknowledgements. The authors would like to commemorate the dear friend and colleague Prof. Francesco Benedettini (University of L’Aquila), a great scholar of Structural Dynamics and, specifically, of ambient vibration testing and operational modal analysis methods on bridges. This research was made possible thanks to the interest and the support of the Dipartimento della Protezione Civile of the Friuli Venezia Giulia. The authors would like to gratefully acknowledge the cooperation of Drs. G. Berlasso and C. Garlatti. The collaboration of Prof. Rocco Alaggio and Dr. Daniele Zulli (University of L’Aquila) during dynamic testing is gratefully appreciated. References Alaggio R., Bedon C., Benedettini F., Dilena M., Morassi A. (2015). Ambient vibration testing and structural identification of a cable-stayed bridge. Proceedings of IOMAC’15 – 6 th International Operational Modal Analysis Conference, May 12-14, Gijón, Spain. ISBN 978-84-617-3880-9 ARTeMIS Extractor Software (2002), ver.3.2, issued by Structural Vibration Solution ApS, NOVI Science Park, Niels Jernes Vej 10, DK 9220, Aalgorg East, Denmark Benedettini F., Gentile C. (2011) Operational modal testing and FE model tuning of a cable-stayed bridge. Engineering Structures, 33: 2063-2073 Brincker R., Zhang L., Andersen P. (2001) Modal identification of output-only systems using frequency domain decomposition. Smart Material and Structures 10: 441-445 Caetano E., Cunha Á. (2011) On the observation and identification of cable-supported structures. Proceedings of the 8th International Conference on Structural Dynamics EURODYN 2011 (pp. 17-28). Leuven, Belgium Simulia (2012). ABAQUS v.9.12 computer software Welch P.D. (1967). The Use of Fast Fourier Transform for the Estimation of Power Spectra: AMethod Based on Time Averaging Over Short. Modified Perodograms, IEEE Transactions on Audio Electroacoustics, AU-15, 70-73. INTERVENTO DI COMPACTION GROUTING SU UN EDIFICIO RESIDENZIALE DANNEGGIATO DAL SISMA EMILIANO DEL 2012 A SAN CARLO (FE) PER LA MITIGAZIONE DEL RISCHIO DI LIQUEFAZIONE: PRIMI RISULTATI DI UN CAMPO PROVA A. Colombi, M. Roversi, E. Pallara Colombi & Roversi Associati Studio di Ingegneria, Ferrara, Italia Introduzione. La sequenza sismica padana di maggio-giugno 2012, ha causato vistosi effetti di liquefazione (Crespellani et al. , 2012; EMERGEO, 2012) nell’area dell’alto ferrarese. Molti edifici, residenziali e non, hanno subito danni ingenti a strutture ed elementi non strutturali a causa dei movimenti occorsi a seguito dei fenomeni di liquefazione avvenuti. L’edificio oggetto di intervento è una struttura danneggiata durante il terremoto del maggio 2012 che rientra nella cosiddetta zona azzurra dell’abitato di San Carlo ovvero nelle aree nelle quali si sono manifestati gravi effetti di liquefazione a seguito del sisma (Determinazione RER n. 12418/2012).