Reliability analysis of a reinforced concrete drainage structure

A reliability assessment was performed to examine potential modes of unsatisfactory performance for a six-barrel gravity drainage structure and pumping plant located under a 33-ft-high levee section. The structure is composed of reinforced concrete which has suffered severe structural deterioration and exposure of reinforcement. This structure is a critical element in the levee system that protects a major metropolitan area from river and bayou flooding. Loss of this structure during a projected flood event would lead to a high probability of loss of life because of its proximity to a highly populated area. Using soil-structure interaction analyses, the outer culvert wall was modeled as a beam-column subjected to lateral and vertical earth pressures, and hydrostatic water pressures. Monte Carlo simulations and first-order second-moment techniques were utilized to examine the reliability of the culvert for normal operating conditions and for projected floods of 50 and 100 years.