PSI - Issue 78

Marco Nale et al. / Procedia Structural Integrity 78 (2026) 1095–1102

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assess the operational status. If a malfunction is detected, the inspection is extended to the related components, such as relays, surge protection devices, or wiring, to identify potential cases of failure. Similar checks shall be extended to emergency generators, control systems, and monitoring instruments. Functionality tests for mechanical components are expected following the activation of CL1. For example, gate tests include opening and closing to verify damage. In the case of minor defects, the test may be carried out using assisted electrical systems when the system is powered. If the electrical system is out of service, the manual system shall be used to check the functionality of the gates. Similar tests are also planned for other mechanical components, such as valves and hydraulic actuators. 2.5. Definition of the damage class and post-earthquake actions After the post-earthquake survey and the results of functionality tests, three damage classes are established: Low (L), Medium (M), and High (H) (Table 1). Classification is specified for electrical and control components, mechanical components, and structural components. The damage class is assigned according to the Defect Severity (DS), Functionality Compromised (FC), and Structural Safety Compromised (SSC), also considering the extension (K 1 ) and intensity (K 2 ) of the damage:

Table 1. Damage Class (DC) definition criteria. Damage Class (DC)

Definition

High (H)

Presence of components affected by DS = 4 or DS = 5 with high extension (K 1 = 1) and intensity (K 2 = 1) or presence of critical conditions that may lead to FC or SSC. Presence of components affected by DS = 4 or DS = 5 with moderate extension (K 1 = 0.5) and intensity (K 2 = 0.5) but not leading to critical conditions such as FC or SSC. Presence of components with DS ≤ 3 and low to moderate extension and intensity.

Medium (M)

Low (L)

Depending on the class of damage assigned, specific post-earthquake actions are planned:  High damage class (H): repair and testing of damaged components, the inspection of secondary systems, and possible reduction of hydraulic flow during repair operations, and functional verification of the post-intervention system. In the event of severe structural damage, prompt action is required, including detailed measurements, restoration efforts, and reinforcement measures.  Medium damage class (M): replacement and testing of damaged components. Verification of the operation of secondary control systems and remote controls is also required, especially if the main control structure becomes temporarily unusable. If the secondary systems cannot promptly guarantee hydraulic safety, the possibility of lowering the hydraulic level should be evaluated in coordination with infrastructure managers.  Low damage class (L): repair of the damaged component, since the damage is limited in scope and spread. The proposed classification procedure represents a first operational scheme for the rapid assessment of post-seismic damage, based on an essentially observational approach. It will be necessary to calibrate the procedure following an extended application in different seismic scenarios and in territorial contexts other than that of the Po Valley considered in this study. A possible limitation of the proposed procedure concerns the specificity of the types of hydraulic infrastructure to which the study refers. 3. Validation of the protocol The protocol has been validated employing the 2012 Emilia earthquake scenarios. For the sake of brevity, the scenario of the first shock is reported on May 20, 2012. Fig. 3a presents the ShakeMap for the seismic event, illustrating PGA attenuation and inspection areas. On this map, the locations of the studied hydraulic structures are also indicated. The areas subjected to inspection according to Circular SDI/3536 (IMIT,2002) and its updates (IMIT,2017) are shown using concentric rings: a black dashed circle represents the 2002 protocol, a magenta circle