Two Alternative System Reliability Approaches to the Serviceability Condition Assessment of Spillway Gate Systems on Dams
The U.S. Army Corps of Engineers is one of the Nation’s largest managers of infrastructure. It is responsible for maintaining and operating the Nation’s navigable waterways and is the primary agency for maintaining federal flood control dams. This includes a vast amount of infrastructure that includes roughly 270 navigation dams, 350 reservoir dams, and 238 lock chambers (Bullock and Foltz 1995). The navigable inland waterways carry roughly 17% of the Nation’s intercity cargo – an important economic role (USACE 2004). Over half of the locks and dams are over 50 years old. The entire inventory is deteriorating over time and requires billions of dollars to upgrade, maintain, and repair. The Corps of Engineers requires that a strength-based reliability analysis be completed to justify major rehabilitation projects. Reliability methods are preferred for cost-benefits analyses and for quantifying risk. More often, however, it is the general serviceability of a structure that dictates the requirements for maintenance and repair. The Corps of Engineers has developed a Condition Index (CI) rating system for a variety of structures that assesses the general serviceability condition of a structure based on periodic visual inspections. A Condition Index (CI) is a rating between 0 and 100 that describes the condition of a structure at a point in time. The CI is based on a series of observations by an inspector. At the component level, the inspector classifies what he or she sees into the predefined descriptive category that best matches the observation. Some CIs also include measurements. More often, the condition scores are based on descriptive word pictures that are often vague and difficult to quantify. Chouinard et.al. (2003) developed a deterministic CI rating system for spillway gate systems on dams. The gate system contained 122 separate inspectable components, each with its own condition rating table. The structure was decomposed into a seven-level structural hierarchy of systems, sub-systems, and components. The highest levels are shown in Figure 1. Estes et.al. (2005) developed a reliability-based approach that assigns probabilistic CI ratings for groups of components, systems, and projects. The approach accounts for the considerable uncertainty associated with the CI process which includes: • Uncertainty in the ability of different inspectors to reliably choose the correct condition state and to a greater degree, the appropriate score within a condition state 17 ANALYSIS AND COMPUTATION SPECIALTY CONFERENCE th
Objective Procedure for Optimization of Inspection and Testing Strategies for Spillways
AbstractThe 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...
Research on Control and Planning of Soft-Wing UAV for Haze Removal
The existence of fog and haze has caused great pollution to the environment. The research of removing haze is a hot topic in recent years. In this paper, a special haze removal algorithm based on Soft- Wing UAVis proposed. In this algorithm, two track control strategies are designed based on the Soft-Wing UAV model transfer function. A SIMULINK platform based mathematical model of Soft-Wing UAV is built to testified effectiveness of the two track control strategies. An autonomous ergodic-planning algorithm with greedy strategy and foldback algorithm for Soft-Wing UAV is designed. Within the algorithm, the haze regional has been modelled, the cost matrix is constructed, and the planning and ergodic strategy is proposed. Finally, the experimental results validates the reliability of the algorithm in the application of haze removal with the proposed evaluation Index.