PSI - Issue 78

Matteo Tatangelo et al. / Procedia Structural Integrity 78 (2026) 73–80

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6. Conclusions This paper presents a reliability-based seismic approach for calibration of target reliability indexes in a certain reference period by examining the entire Italian territory. The calibration requires to know of the fragility curves parameters, corresponding to ̂ and . In particular, refer to literature studies, while median value has been found by adopting the target reliability factor , by modifying the � . As ̅ , , the values of as unknown, therefore in order to calibrate new values of target reliability indexes, has been derived starting from the unique reference of target failure nowadays present within the seismic codes. The model developed was then applied on the Italian territory in order to observe the consequences that a reliability based framework would have for the design and assessment of constructions in order to have uniform structural reliability. The results show that seismic sites with low hazard require amplification of design actions, while high hazard sites should be de-amplified. This is a consequence of the fact that the proposed target reliability indexes refer to mean values over the Italian territory. However, the choice of a different fractile should be specified by the competent authorities. Furthermore, a corrective parameter 0 is introduced that would make it possible to take into account the strength reserve in constructions due to the partial factors on materials. In this way, both non-seismic and seismic conditions would fall within a common reliability framework based on partial factors. A remark is due on the corrective parameter 0 for the use of partial factors, a key issue in the standard framework. The correct calibration of this parameter would make it possible not to have to radically change the now consolidated way of designing based on partial factors. This would require knowledge of the reserve of strength that these provide to the constructions. Further research could focus on extending this approach incorporating more refined probabilistic models for ground motion intensity measures that take into account regional seismic source characteristics could further improve the accuracy of the proposed methodology. In addition, alternative formulations for the target reliability factor could be investigated and, in particular, the issue of the increase in resistance that partial factors provide to the construction should be addressed. References ASCE, 2016. Asce/sei 7-16 Minimum Design Loads and Associated Criteria for Buildings and Other Structures. (American Society of Civil Engineers, 2016). Bradley, B.A., Dhakal, R.P., Cubrinovski, M., Mander, J.B., & MacRae, G.A., 2007. Improved seismic hazard model with applicat ion to probabilistic seismic demand analysis. Earthquake Engng Struct. Dyn.; 36:2211–2225. DOI: 10.1002/eqe.727. 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