GNGTS 2021 - Atti del 39° Convegno Nazionale

GNGTS 2021 S essione 2.2 332 Conclusions It should be underlined that all the considerations briefly reported in this abstract are purposely kept general: no specific reference is made to any construction type (either bridge or building), nor to the definition of damage/limit states, nor to the nature of the FC (either analytical or observational), nor to the functional form adopted for the FC (either lognormal, or logistic, or any other). The considerations we followed to develop a closed-form transformation are of analytical nature and, as such, are suitably general to be applied to any FC, regardless of how it is obtained. A FC is regarded as a function, as it actually is, which undergo a nonlinear transformation when subjected to different response spectra. The obtained transformation is a useful tool to derive families of FCs, which possess distinct features when placed at different locations and on different soils. Such transformation has been compared to a more simplistic analytical transformation that amounts to shifting the median of the FC by the local soil amplification factor. Such approach, though simpler, produces unacceptable estimation errors, thus leading to gross underestimates that can affect scenario and risk assessment studies. Acknowledgements The ReLUIS 2019-2021 project is acknowledged for the financial support given to this study. References A.H.S. Ang, W.H. Tang, Probability concepts in engineering. Vol. 1, Basic principles, 1975. A.J. Kappos, G. Panagopoulos, C. Panagiotopoulos, G. Penelis, A.J. Kappos, · G Panagopoulos, · C Panagiotopoulos, · G Penelis, A hybrid method for the vulnerability assessment of R/C and URM buildings, Springer. 4 (2006) 391–413. https://doi.org/10.1007/s10518-006-9023-0. T. Rossetto, I. Ioannou, D. Grant, Existing empirical fragility and vulnerability functions: compendium and guide for selection, 2013. T. Rossetto, I. Ioannou, D. Grant, T. Maqsood, Guidelines for empirical vulnerability assessment. Vol. 6, 2014. Corresponding author: giorgio.monti@uniroma1.it Fig. 2 - Left: the FC on soil A (solid red) is transformed on soil C with both an exact soil-dependent approach (solid yellow) and a simplistic approach (dashed brown) accounting for soil through a shift. Right: underestimation of the exceedance probability of the simplistic FC with respect to the exact one. For example, at 0.2g the simplistic curve predicts 50% of the actual exceedance probability. Scenario and risk assessment studies can be grossly underestimated.