PSI - Issue 78

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

1097

2. Proposed protocol The functionality of hydraulic structures following a seismic event is evaluated through the selection of the Control Level (CL). Three control levels are defined: Level 0, Level 1, and Level 2. These CLs are activated by PGA detected on site, as determined by the Shake Maps generated after the seismic event. The acceleration threshold values, referred to as a g1 and a g2 , are established in relation to the specific vulnerability of the hydraulic structure and permit the selection of an appropriate control level. Each control level entails specific inspections of the components that constitute the hydraulic infrastructure (Fig. 2). More precisely, CL0 focuses on the gas system, electrical power supply, and control components. CL1 includes all CL0 controls with the addition of mechanical component controls such as gates, pistons, or valves. Finally, CL2 comprises all previous control levels and further adds the structural components controls.

In case of extensive structural damage

CL2 • Structural components  RCbeams

CL0

CL1

•

Gas system

•

Mechanical components  Principal gates  Temporary gates  Miter gates 

 Steel beams  RCcolumns  Steel columns  RC shear walls  Masonry Walls  Floor slabs  RCSlabs  Roofs

•

Electrical power supply 

General electrical power supply Electrical power supply (for any device) Emergency electrical power supply

 

Pistons of oleodynamic systems

Valves



•

Control components 

Control unit for gate

Hydraulic system control unit Level monitoring instruments

 

• Bridges

Fig. 2. The components considered at each control level are summarized: Control Level 0 (CL0) comprises components related to gas supply, electrical power supply, and control systems; Control Level 1 (CL1) covers the mechanical components involved in the hydraulic operations; and Control Level 2 (CL2) focuses on the structural components of the infrastructure. 2.1. Acceleration threshold control levels In the proposed protocol, the selection of control levels is linked with vulnerability and, in particular, with the definition of acceleration thresholds as follows:  a g1 is the acceleration associated with a probability of exceeding 10% on the fragility curve of the most vulnerable mechanism or structure within the hydraulic structure. This value defines the trigger threshold for the Control Level 1.  a g2 is the acceleration that activates Control Level 2 and is represented by the average value (50% probability of exceeding) of the fragility curve relative to the most vulnerable mechanism or structure of the hydraulic infrastructure. When fragility curves are available for each damage state, as in the case of the HAZUS methodology (FEMA,2022), which aligns with the limit states defined in the codes, it is possible to refer to the mean value of the curve associated with the Operational Limit State (OLS). This value corresponds to the mean value of the damage state where a loss of functionality starts.