PSI - Issue 78

Gloria Terenzi et al. / Procedia Structural Integrity 78 (2026) 341–348

348

Force [kN]

Force [kN]

BC1BN-FC T10-2025

BC1DN-FC T13-2025

a)

b)

Fig. 6. Selected experimental (blue line) and numerical (red line) hysteretic cycles deriving from a part of F t -d i results derived from T10 and T13 tests carried out with  =5 Hz on BC1BN-FC (a) and BC1DN-FC (b) dampers. 4. Conclusions The results of the testing campaign carried out in 2025 on a BC1BN-FC and a BC1DN-FC pair of PFV spring dampers show very similar values of their mechanical characteristics to the ones derived from the 2008 tests. Indeed, identical values of the second-branch stiffness of the non-linear elastic spring component, k 2 , equal to 1.2 kN/mm (BC1BN-FC) and 1.4 kN/mm (BC1DN-FC) are derived from the results of the two experimental campaigns. At the same time, the identification analysis of the damping coefficient, which in principle could be the most sensitive parameter to aging effects, highlights almost coincident mean values for the two data sets, both in quasi static and dynamic response conditions. For the latter, c id values varying in a narrow range around 3.3 kN(s/mm)  are always obtained, starting from frequencies of 1 Hz up to 10 Hz—corresponding to applied velocities from about 45 mm/s to 470 mm/s—for the BC1BN-FC damper pair, and around 6 kN(s/mm)  , starting from frequencies of 1 Hz up to 8 Hz—corresponding to applied velocities from about 60 mm/s to 412 mm/s—for BC1DN-FC damper pair. Although limited to two pairs of devices, the results of this first section of the study support the hypothesis of negligible aging effects on the response capacities of pressurized fluid viscous dampers. Moreover, by comparing T10 and T13 test results, added to the 2025 campaign, with the corresponding T7 and T9 2025 tests, a negligible variation of c id values is observed, assessing the stability of the mechanical behaviour of PFV devices over a high number of response cycles. Acknowledgements The study reported in this paper was sponsored by the Italian Department of Civil Protection within the ReLUIS DPC Project 2024/2026, WP 15 “Devices and systems for base isolation and supplemental damping dissipation”. The authors gratefully acknowledge this financial support. References Jarret SL, 2007. Shock-control technologies, URL http://www.introini.info. Sorace, S., Terenzi, G., 2001. Non-linear dynamic modelling and design procedure of FV spring-dampers for base isolation. Engineering Structures 23, 1556–1567. Sorace, S., Terenzi, G., 2008. Seismic protection of frame structures by fluid viscous damped braces. ASCE Journal of Structural Engineering 134, 45–55. Sorace, S., Terenzi, G., Fadi, F., 2012. Shaking table and numerical seismic performance evaluation of a fluid viscous-dissipative bracing system. Earthquake Spectra 28, 1619–1642.