Condition assessment and rehabilitation of large sewers

The Urban Infrastructure Rehabilitation Program of the National Research Council Canada (NRC) in conjunction with 10 municipalities and two consulting companies has just completed a set of guidelines focusing on the impact and condition assessments, and rehabilitation of large diameter sewers (> 900 mm) as well as access holes. The guidelines provide a consistent approach for assessing the impact of pipe failure, coding defects and assigning priorities for rehabilitation. The user-friendly approach is demonstrated with an example. By using unified definitions of terminology and a consistent defect coding system, information can be shared between utilities across the country. Pooling scarce sewer condition data from various municipalities across Canada will enable the development and verification of statistical models for assessing sewer deterioration and predicting its remaining service life. and the relationships between each step will be discussed in detail in the following sections. Figure 1. Approach for managing sewer assets