Estimating Risk from Spillway Gate Systems on Dams Using Condition Assessment Data

摘要

Inland waterways maintained by the U.S. Army Corps of Engineers carry about 17% of the nation's intercity cargo, so service interruptions related to waterway infrastructure failure can cause substantial economic loss. Maintenance and repair (M&R) requirements for navigation structures compete for funding with every other national priority, however, and Federal budgeting decisions are determined largely on the basis of net benefit to the nation per dollar invested. The Corps uses analytical tools and methods to help objectively determine project benefits versus costs. In Corps cost/benefit analyses for navigation structures, reducing the risk of failure through repair or rehabilitation is quantified as a benefit. Conventional reliability-based risk analysis is costly and complex, however. This study investigated the adaptation of an existing condition indexing (CI) methodology to assess overall structural risk and failure probability. It was concluded that a risk based analysis, using the well established concepts of a reliability index, failure probability, hazard function, and cost/benefit analysis, is possible and feasible. Because CI data have not been systematically collected and are not available, the methodology proposed here remains untested. A number of reasonable assumptions made in this study have not yet been verified using actual CI data collected over time from existing projects.