Objective Procedure for Optimization of Inspection and Testing Strategies for Spillways

Abstract

The function of a spillway gate system is to control the flow of water through an opening for purposes such as flow regulation, flood control, emergency water release during load rejection, and dewatering for maintenance operations, or to remediate or respond to structural deficiencies. A growing problem for dam owners is the aging of such structures. As spillway systems age, more rigorous maintenance, inspection/testing, and repair/replacement of parts are required to ensure their long-term safe operation. Executing these measures may be very costly to dam owners and, if not conducted appropriately, may not have the desired effect on the reliability of the system. The first objective of this paper is to investigate the effect of inspection, testing, repair, and replacement strategies on the availability of spillway gate components. The second objective is to model the availability of the entire spillway gate system under flood and load rejection scenarios to determine the ability of the system as a whole to operate safely under emergency conditions. These two objectives are then used with cost optimization to develop recommendations on the type and frequency of inspections and tests for different types of spillway gate systems. A software application was developed to achieve the objectives by modeling the spillway gate components and system, determining component/system unavailability based on type and frequency of inspections/tests, and obtaining the optimum inspection/testing strategy.