PSI - Issue 44

Paola Sorrentino et al. / Procedia Structural Integrity 44 (2023) 1300–1307 Paola Sorrentino et al. / Structural Integrity Procedia 00 (2022) 000–000

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strictly connected to the increasing number of seismic arrays for recording ground motions and the consequent availability of the number of strong motion data. If we look back, in the history of earthquake engineering, 1940 El Centro Earthquake have represented a milestone: its maximum recorded peak ground acceleration of 0.35g, corresponding to a spectral acceleration of 0.90g, have influenced the definition of seismic design actions in all building codes, even today based on the probabilistic response spectrum approach. However, data from recent earthquakes have pointed out some “faults” in this procedure, introducing many questions about the achievement of actual seismic design methods. As argued in this paper, the analysis of spectral values from recent earthquakes underlines that seismic actions are really much higher than the ones defined according to codes. This leads to look for effective design strategies that can accomplish the need of wider horizontal displacements, always preserving devices’ stability in accommodate large shear deformations. However, this unexpected design demand, derived from the elaboration of spectral data, cannot be effectively counteracted. Also in the case of new buildings, it is impossible to face a seismic force ten-time greater its own weight or to accommodate displacements greater than devices dimensions. Therefore, a better quality in construction and a higher accuracy in details are required to contribute to structural safety. Acknowledgements The support provided by consortium ReLUIS is acknowledged. The activities are related to the topics of WP5 “Interventi di rapida esecuzione a basso impatto e integrati” e and W15 “Isolamento e dissipazione”, included in the project DPC-ReLUIS 2019-2021. References Architectural Institute of Japan (2016). “Design Recommendations for Seismically Isolated Buildings”. 4th Edition. Campbell, K.W., Bozorgnia, Y: (2007).” NGA Ground Motion Relations for the Geometric Mean Horizontal Component of Peak and Spectral Ground Motion Parameters” Report No. UCB/PEER 2007/02. Pacific Earthquake Engineering Research Center, University of California, Berkeley. Campbell, K.W., Abrahamson, N., Power, M., Chiou, B., Bozorgnia, Y., Shantz, T., Roblee, C., (2009). “Next Generation Attenuation (NGA) project: empirical ground motion prediction equations for active tectonic regions”. Sixth International Conference on Urban Earthquake Engineering. March 3-4, 2009, Tokyo Institute of Technology, Tokyo, Japan. Chiou, B.J., Youngs, R.R., (2008). “NGA Model for Average Horizontal Component of Peak Ground Motion and Response Spectra”. UCB/PEER 2008/09. Pacific Earthquake Engineering Research Center, University of California, Berkeley. De Luca, A. and Guidi, L.G. (2019). “State of Art on the Worldwide Evolution of Base Isolation Design”. Soil Dynamics and Earthquake Engineering, 125 (2019) 105722. https://doi.org/10.1016/j.soildyn.2019.105722. De Luca, A. and Guidi L.G. (2020). “Base isolation issues in Italy: Integrated Architectural and Structural Design”. Soil Dynamics and Earthquake Engineering, 130 (2020) 105912. https://doi.org/10.1016/j.soildyn.2019.105912 De Luca, A., Guidi, L.G., Brandonisio, G., Ponzo, F.C., (2022). “Horizontal capacity of base isolation rubber devices under large vertical design stress, valued through full-scale tests”. Soil Dynamics and Earthquake Engineering. Volume 159, August 2022, 107264. https://doi.org/10.1016/j.soildyn.2022.107264. Kaklamanos, J., Boore, D.M., Thompson, E.M., Campbell, K.W., (2010). “Implementation of the Next Generation Attenuation (NGA) ground motion prediction equations in Fortran and R”. U.S. Geological Survey Open-File Report 2010–1296, in cooperation with Tufts University. https://pubs.er.usgs.gov/publication/ofr20101296. FEMA-307 1999. Evaluation of Earthquake damaged concrete and masonry wall buildings – Technical Resources. Federal Emergency Management Agency, Washington, D.C. Kelly, T.E., 2001. Base isolation of structures: Design guidelines. Wellington, New Zealand: Holmes Consulting Group Ltd. Miyazaki, M., 2008. The Next Generation of Seismic Isolation. Going Beyond Seismic Design Dominated by Earthquakes. In: Journal of Disaster Research Vol.3 No.6, pp. 479-502. Power, M., Chiou, B., Abrahamson, N., Bozorgnia, Y., Shantz, T., Roblee, C., (2008). “An Overview of the NGA Project”. Earthquake Spectra - February 2008, Volume 24, Issue 1, pp. 3-21. Suzuki, A., Iervolino, I., 2017. Italian vs worldwide history of largest PGA and PGV. In: Annals of geophysics, 60, 5, 2017; S0551; doi: 10.4401/ag 7391.