## 6 Conclusions  
In this paper the experimental dynamic hysteretic behavior of different flexural steel dampers for dissipative bracing systems was investigated in terms of number of cycles at different ductility levels and compared with quasi-static cyclic testing requirements of main seismic codes and guidelines.  
Two experimental case studies of a two-story steel frame and of a three-story post-tensioned timber frame both with dissipative bracing systems including flexural steel dampers, hysteretic dampers (HDs), and U-shaped flexural plates (UFPs), respectively, were considered in this study. The experimental braced frames were tested on the shaking table available at the structural laboratory of the University of Basilicata. The steel braced frame (SBF) and the post-tensioned timber braced frame (TBF) have different stiffness properties, designed based on DBD procedure at target design drift of 0.5% for the SBF and of 1.25% for the TBF. Controlled-displacement cyclic tests were carried out using different loading protocols in accordance with European code (EN 15129) for HDs and American guidelines (FEMA 461) for UFPs.  
Shaking table tests were performed considering the same seismic sequence composed by a set of seven natural spectra-compatible earthquakes at increasing PGA levels. The main global key parameters highlighted that both frames responded with comparable base shears and top accelerations and with different displacements and drifts, due to the stiffness of SBF model higher than the TBF model. As expected, the global force-displacement behavior showed the hysteretic and flag-shaped responses of SBF and of the post-tensioned TBF, respectively. The HD and UFP dampers, provided ductile and stable performances with excellent dissipative capacity also when the displacement exceeded the design value. More than one hundred inelastic cycles were experimentally recorded from more than 20 earthquakes at increasing PGA levels before the failure of devices for both experimental models, with negligible residual drift and complete re-centering of seismic displacement without damages to the structural elements.  
The number of cycles under the design earthquakes (PGA 100%) considerably decreases with increasing of ductility demand for both HD and UFP devices. This trend is in line with American standards testing requirements ASCE 7-10 [37] for prototype tests (TT) and in good agreement with the loading history suggested by American guidelines FEMA 461 [38]. The procedure imposed for type tests (TT) and for factory production control tests (FPTC) by European (EN 15,129 [36]) and Italian (NTC 2018 [35]) seismic codes significantly overestimated the number of cycles at the design ductility  
Figure 15: Number of cycles estimated from experimental dynamic tests compared with the codes requirements for (**a**) HDs of the steel braced frame and (**b**) UFPs of the timber braced frame.  
for both experimental case studies. Moreover, the number of devices required for FPCT by the NTC 2018 appear redundant compared with EN 15129, this becomes uneconomical especially in case of supply of few steel-based dampers unusable after testing.  
Conceptualization, A.D.C. and F.C.P.; methodology, A.D.C., F.C.P., and N.L.; experimental investigation, F.C.P., A.D.C., and D.N.; numerical analysis, A.D.C. and N.L.; data processing, N.L.; project administration, F.C.P. and A.D.C.; funding acquisition, F.C.P. and D.N. All authors have read and agreed to the published version of the manuscript.  
This study was supported by RELUIS 2019-2021 project funded by the Italian Civil Protection Department.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.