# Investigating the Reliability of Nonlinear Static Procedures
## 5 Results  
The outcomes obtained by applying nonlinear static and dynamic analyses are compared in this section in terms of the fragility curves, focusing on the impact of various options for the application of the NSPs (see Section 2), namely related to the choice of the method used to calculate the displacement demand (i.e., whether based on the use of inelastic or overdamped spectra) (Section 5.1) and the approach adopted for the bilinearization of the pushover curve (Section 5.2). As already mentioned, the fragility curve from the NLDA is assumed as a reference to check the reliability of the different alternatives explored for NPSs and determine the most effective one, as illustrated in Figure 10 and extensively discussed in the following sections. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c c c c c c c c c c  
Influence of the Approach Adopted to Compute the Displacement Demand in N2-Based and CSM-Based Methods  
Figures 11-13 illustrate, for the C, A, and B cases, respectively, the comparison of the fragility curves obtained from the ADNL (thick solid black line) and different NSPs (colored lines and dashed/thin black lines). Figure 11: Configuration of Visso C’s fragility curves: in the first column is the X-analysis, and in the second column is the Y-analysis; the method of bilinearization of the capacity curve is fixed (in order of row according to Updating ECS-3 rel.2019 [56], NTC18 [8], [PERSON] et al., 2019 [32]) and we include all the possible methods to calculate the displacement capacity (N2 [PERSON] [33], N2 [PERSON] [57], N2 [PERSON] [32], CSM [34]). Figure 10: Procedure adopted to assess the reliability for various NSPs. More specifically, the red line refers to the original N2 method; the blue line to [PERSON]'s proposal; the green line to [PERSON]'s proposal; and the dashed and thin black lines to the CSM approach, with two different values adopted for the dissipation properties (i.e., k = 0.33 thin solid line and k = 0.66 dashed line). Each figure is arranged in such a way as to present, in the left column, results from the X-direction and, in the right column, results from the Y-direction; in each line, the results are associated with the NSP applied according to the specific choice of the criterion for the equivalent bilinearization of the pushover curve (i.e., the first line according to Updating EC8-3 rel.2019, the second line to NTC2018, and the third line to [PERSON]'s proposal). For all the cases, and especially for the C, A, and B-X directions, it is evident that, regardless of the method used to address the conversion in the equivalent bilinear of the  
Figure 12: Configuration of Visso A’s fragility curves: in the first row is the X-analysis, and in the second row is the Y-analysis; the method of bilinearization of the capacity curve is fixed (in order of row according to Updating EC8-3 rel.2019 [56], NTC18 [8], [PERSON] et al., 2019 [32]) and we include all the possible methods to calculate the displacement capacity (N2 [PERSON] [33], N2 [PERSON] [57], N2 [PERSON] [32], CSM [34]). pushover curve, the NSPs based on the use of inelastic spectra (i.e., according to the N2 or similar methods) show non-conservative behavior (i.e., with fragility curves shifted to the right for the one derived from NLDAs). Moreover, among the three methods based on inelastic spectra, it is possible to observe that the least conservative one is the original N2 method, while [PERSON] and [PERSON]'s proposals produce some improvements (especially in the A and B cases), although, in most cases, they are not sufficient to obtain a fragility curve close to that from the NLDAs. In fact, it can be noted that [PERSON]'s N2 method, i.e., the blue line, is usually to the left of [PERSON]'s N2 method, i.e., the red line.