PSI - Issue 44

Iolanda Nuzzo et al. / Procedia Structural Integrity 44 (2023) 1832–1839 Iolanda Nuzzo et al./ Structural Integrity Procedia 00 (2022) 000–000

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Once calculated the vector “C” through the former equation, the values of this vector are set following the array of Table 2. In this way, the resulting cost matrix for the Section A of the viaduct is shown in Table 3. Consequently, for each level of damage, the lowest cost is obtained by launching a type of alarm proportionate to it (costs on the diagonal). The costs of false alarm are higher since they can induce economic consequences that are not necessary and therefore not foreseen. The costs of missed alarm are instead the maximum possible ones, in how much those that can determine accidentality and relative effects on human health. The second aim of this step is to determine, for each MS, the expected losses given determined intensity measure with the contribution of each DS. This was achieved using the total probability theorem, as reported in (Iervolino et al., 2007). Thus, four expected loss curves are obtained in function of IM in the transversal direction (x), and other four curves for the longitudinal direction (y). M pxq = � | | v CT v CR | | | | v CI v A | | � (1) C px1 = M pxq . a qx1 (2) 2.6 Step 6: Optimal mitigation strategy for loss minimization The number of loss curves obtained during Step 5 corresponds to the number of MSs. According to the loss minimization procedure, the matching between one curve with the inferior envelope determines the ranges where that MS must be launched. The monitoring system analyses the status of different critical components, as described above, establishing alarms of different severity depending on the assigned thresholds. The operation of RRWS is described in Fig. 4. The first row presents the critical components considered, i.e., whose performance describes the possible occurrence of the damage mechanisms identified for the infrastructure under consideration. The second row involves the threshold values that identify the engineering demand parameter of the critical components in longitudinal and transverse directions. The most severe mitigation strategy obtained from the analysis of all critical components is chosen for the final decision. This approach allows making immediate decisions on the entire viaduct after a seismic event. 3 RRSW Implementation The RRWS system is one of the specific objectives of the Risks and Safety Management of Infrastructures at Regional Scale (GRISIS) project. This project has a regional approach considering seismic risk, hydrological hazard and pollutant degradation capacity. To this purpose, it emphasizes specific zones and infrastructures through the continuous analysis of indicators as a result of real-time monitoring. The EAV viaduct constitutes the case study of the platform in terms of seismic risk, which was analysed and monitored through two sections, as discussed in section 2.1. Each of the sections has a digital twin that is fed from a monitoring system. Although these monitoring systems are independent, they can be configured in a complementary manner. However, this study focuses on the digital twin associated with Section A. The sensors of the monitoring system can be analysed individually or through groups oriented to the measurement of acceleration, displacement and deformation. It is worth mentioning that the effect of temperature variation on the reference structure is also studied. Thus, the RRSW is based on the processing of the aforementioned information through a hybrid operation between a web environment (WE) and a local support and storage environment (SE). The latter was carried out through microcomputers installed on the viaduct, where the processing and storage of the information captured by the sensor networks is performed. While the WE is mainly Table 3. Cost matrix for Section A (in k€). Section A DS 0 DS 1 DS 2 DS 3 MS 0 MS 1 MS 2 MS 3 0.00 13.92 264.00 19,165.72 60,484.04 91.92 19,092.64 60,498.00 153.15 231.15 167.04 245.04 654.68 668.57 23,110.05 17,759.19