PSI - Issue 44

Agnese Natali et al. / Procedia Structural Integrity 44 (2023) 2012–2019 Agnese Natali et al./ Structural Integrity Procedia 00 (2022) 000–000

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these parameters are pre-fixed). It is also necessary to report if the analysed component is a critical one, meaning a component that is characterized by potential fragility, and whose crisis may induce the crisis of the whole structure or of one of its components. An example of a critical element is a dapped-end, whose crisis is connected to shear fragile mechanisms, causing if occurring the collapse of the beam. The Operating Instructions provide additional suggestions for the correct execution of the inspections, starting, as an example, from the univocal individuation of the components with their defects, which position has to be clearly identified in the component itself. Pictures of the components and their defects shall be collected, in order to have the chance to control the evolution of damage with the time. The correct execution of the visual inspections is fundamental for the process of the classification, since it is the base for the definition of the “level of defectiveness” of the structure, which is one of the most influencing parameters for the evaluation of the structural and seismic vulnerability of the bridge and, consequently, for the structural and seismic WaC. 2.3. The Level 2 The Level 2 is the classification process: for each considered risk, the classification is performed by combining hazard, vulnerability and exposure (as the standard base procedure for a risk analysis), but using an easily-applicable approach made of logical flows and tables. The hazard, vulnerability and exposure parameters are separately evaluated taking into consideration and connecting the previously gathered parameters (from Level 0 and Level 1) according to logical flows. As an instance, Table 1 shows the parameters to consider for the definition of hazard, vulnerability and exposure for the structural risk, and Fig. 1 shows the logical flow for the evaluation of vulnerability. Vulnerability, exposure and hazard are identified by 5 classes (low, low-medium, medium, medium high and high), as the WaC for each risk and the final global WaC of the bridge.

Table 1. Parameters for the definition of the structural and foundational warning class. Primary parameters

Secondary parameters

Extent and frequency of loads with particular reference to the transit of special transport - Defectiveness, static scheme, span length, materials and number of spans Average Daily Traffic (ADT) and average span length

Hazard

Vulnerability

Rapidity of degradation evolution, Design standard Alternative routes, Typology of crossed obstacle, Transit of dangerous goods

Exposure

Fig. 1. Logical flow for the evaluation of the vulnerability for the structural warning class.