PSI - Issue 78

Giulia Giuliani et al. / Procedia Structural Integrity 78 (2026) 952–959

959

5. Conclusions This study provides a comprehensive assessment of the influence of near-fault ground motions on the design of base-isolated reinforced concrete buildings. The analysis focuses on isolation systems comprising High Damping Rubber Bearings (HDRBs), both as standalone devices and in combination with low-friction Flat Slider Bearings (FSBs). The findings indicate that the design of seismic isolators is highly sensitive to the proximity of the structure to the fault rupture, necessitating site-specific ground motion input that accurately represents both horizontal and vertical components. Moreover, rigorous selection criteria for tri-axial accelerogram sets are essential to ensure compatibility with the target spectra across relevant vibration periods. At very short fault distances, the design becomes considerably more demanding and cost-intensive due to the increased rubber volume required and the greater number of FSBs needed to satisfy stability criteria. Additionally, significant vertical ground motion may induce uplift or tension in the isolation bearings — phenomena that pose critical design challenges and warrant further in-depth investigation. These results underscore the necessity for refined design methodologies and potential code updates to ensure the reliability of base-isolated systems in near-fault seismic environments. References ASCE 7 (2022)Minimum Design Loads and Associated Criteria for Buildings and Other Structures. American Society of Civil Engineers, Reston. Baker JW. Quantitative Classification of Near-Fault Ground Motions Using Wavelet Analysis. Bulletin of the Seismological Society of America 2007;97:1486–501. Boore DM. Orientation-Independent, Nongeometric-Mean Measures of Seismic Intensity from Two Horizontal Components of Motion. Bulletin of the Seismological Society of America 2010;100:1830–5. Micozzi F, Flora A, Viggiani LRS, Cardone D, Ragni L, Dall’Asta A. Risk Assessment of Reinforced Concrete Buildings with Rubber Isolation Systems Designed by the Italian Seismic Code. Journal of Earthquake Engineering 2022;26:7245–75. EN 1998-1 (2005) Eurocode 8 Design of structures for earthquake resistance Part 1: General rules, seismic actions and rules for buildings, European Committee for Standardization CEN, Brussels EN 15129 (2009) Anti-seismic devices. 2009. European Committee for Standardization CEN, Brussels Erdik M, Şadan B, Tüzün C, Demircioglu -Tumsa MB, Ülker Ö, Harmandar E. Near-Fault Earthquake Ground Motion and Seismic Isolation Design. In: Cimellaro GP, editor. Seismic Isolation, Energy Dissipation and Active Vibration Control of Structures, vol. 309, Cham: Springer International Publishing; 2023, p. 117–52. https://doi.org/10.1007/978-3-031-21187-4_9. Giuliani G. Sgobba S., Micozzi F., Ramadan F., Ragni L., Lanzano G., Luzi L., Dall’Asta A. Three-dimensional seismic input for near fault scenarios and effects on structures. In COMPDYN Proceedings , COMPDYN, 2025. Lanzano G, Luzi L, Pacor F, Felicetta C, Puglia R, Sgobba S, et al. A Revised Ground‐Motion Prediction Model for Shallow Crustal Earthquakes in Italy. Bulletin of the Seismological Society of America 2019;109:525–40. Petricca, P.; Bignami, C.; Doglioni, C. The Epicentral Fingerprint of Earthquakes Marks the coseismically Activated Crustal Volume. Earth-Science Reviews 2021, 218, 103667 Ramadan F, Smerzini C, Lanzano G, Pacor F. An empirical model for the vertical‐to‐horizontal spectral ratios for Italy. Earth q Engng Struct Dyn 2021;50:4121–41. Sgobba S, Felicetta C, Lanzano G, Ramadan F, D’Amico M, Pacor F. NESS2.0: An Updated Version of the Worldwide Dataset for Calibrating and Adjusting Ground-Motion Models in Near Source. Bulletin of the Seismological Society of America 2021;111:2358–78.