Reliability assessment and acceptance criteria for existing hydraulic gates considering corrosion deterioration

This paper develops a procedure to evaluate the time-dependent reliability of existing hydraulic gates subjected to corrosion deterioration. A consistent basis for the representation of the loads acting on the hydraulic gates is provided. The corrosion data for existing hydraulic gates in eight hydropower projects located throughout China are presented. A corrosion model is suggested and its parameters are estimated based on the collected corrosion data. A resistance model for hydraulic gates on the basis of the corrosion model is proposed in terms of the initial ultimate limit state capacity of the component and a degradation function. Reliability analysis is performed to investigate the effect of corrosion rate, safety level of hydraulic gates, and types of hydraulic gates on the reliability of hydraulic gates. Reliability acceptance criteria are inferred corresponding to the current Chinese requirement for the design of hydraulic gates. The conclusions and the proposed approach can be used for guidance to assess the reliability and acceptability of hydraulic steel gates and form a basis for reliability updating, and inspection and maintenance planning.