Temporal global sensitivity analysis of concrete sewer pipes under compounding corrosion and heavy traffic loads

Abstract

During their lifetime, sewer networks face risks of infiltration or exfiltration, restriction of flow capacity, and loss of structural integrity. These factors individually or combined can impact the public health and the environment. This study is aimed at analyzing uncertainties contributing to the service life performance of sewer pipes under compounding effects of corrosion deterioration and traffic loads using a global sensitivity analysis (GSA). The specific goals are to identify significant sources of uncertainty, and to quantify and rank their time-varying significance for extended time horizons. The study considers a comprehensive set of uncertain environmental, structural, and geotechnical variables. Results indicate that among all the material properties, tensile and compressive strength of concrete are the most influential parameters over the entire service life of sewer pipes. According to the results, the significance of environmental variables varies considerably with time. Dissolved sulfide concentration and pH-dependent factor for the proportion of in wastewater significantly affect infiltration/exfiltration for pipes that are older than 30 years. Variables contributing to truckload including the truck weight and multiple presence factor are also found to be significant.