**8. Conclusions**

This article has examined the relationships between the principles of semi-probabilistic reliability assessment of building structures according to the EN1990 standard and reliability-oriented sensitivity analysis (ROSA). The probability distributions of load and resistance close to Gaussian have been considered.

The article proposes new tools for performing ROSA. It has been shown that ROSA can be credibly evaluated using total indices of quantiles of resistance and load action, without the need to study the failure probability. ROSA of design quantiles gives the same sensitivity ranking as the two types of ROSA oriented to failure probability. Although this conclusion has been established based on one case study, the initial results suggest the possibility of using quantile-oriented ROSA in structural reliability studies. It should be interesting to develop a general approach for determining how to combine the various known indices, and in what order, in order to tackle a reliability task.

New quantile-oriented sensitivity indices denoted as QE indices have been formulated in the article. The first study showed that the distance between the quantile and the average value can be a very interesting measure of sensitivity, with the possibility of further development.

The apparent efforts to develop new types of sensitivity analyses show that the scientific community is still looking for the right combination of computational methods to solve specific problems. An important problem in structural reliability analysis is how to reduce the failure probability. Research focused on design quantities complements the development of failure probability estimation methods.

In engineering applications, the inclusion of quantile-oriented sensitivity analysis among the tools for assessing the effects of input variables on reliability makes it possible to effectively reduce the computational cost of sensitivity analysis of reliability with numerically demanding models. An example is the sensitivity analysis of design quantiles of numerous load cases, where the design quantile of the resistance of a structure only needs to be analysed once. It is worth noting that the specification of which parameters constantly appear close to the top of the list with the order of sensitivity is more important than the actual ranking. In practice, we can neglect the discrepancy between rankings for less important variables because these variables have a minimal or no effect on the reliability of structures.

**Funding:** The work has been supported and prepared within the project named "Influence of material properties of stainless steels on reliability of bridge structures" of The Czech Science Foundation (GACR, https://gacr.cz/), No. 20-00761S, Czechia.

**Conflicts of Interest:** The author declares no conflict of interest.
