Reliability Assessment of Reinforced Concrete Sewer Pipes under Adverse Environmental Conditions: Case Study for the City of Arlington, Texas
Khaled Abuhishmeh, Himan Hojat Jalali
Abstract
With aging and deterioration of underground sewer utilities, there is an urgent need for a framework to track their reliability over expected lifetime to facilitate asset management decisions like inspection, maintenance, or replacement. This study proposes multilevel, multifailure framework model for reliability evaluation of reinforced concrete sewer pipe (RCSP) considering the effect of adverse environmental factors such as chloride and sulfide induced attacks, uncertainties in different properties, seasonal temperature and humidity variations, and cracking effects. Monte-Carlo simulation with Latin hypercube sampling is chosen for stochastic analysis to reduce the computational burdens and enhance the accuracy. The application of this framework is illustrated for a case study of an RCSP that has been in service for more than 35 years. Based on results, it is shown that at serviceability stage, sulfide wall erosion is redundant relative to other serviceability issues; therefore, it cannot be used solely for serviceability evaluation of RCSP, as previously done in the literature. At the ultimate level, the effect of chloride pitting corrosion dominates and expedites failure rate. It is proven that there is a huge potential for reinforcement brittle failure under the effect of pitting corrosion, which can lead to a catastrophic collapse.