Marks rating system – an approach in condition assessment and prioritization of sewer rehabilitation – a case study

Abstract

Marks rating system is a simple system that can be used to evaluate the condition of sewer pipes and to determine the prioritization for rehabilitation purposes of sewer pipes and sewer infrastructures. The system provides a consistent approach for assessing the impact of pipe failure, coding defects and assigning priorities for rehabilitation of sewer pipes. Each sewer segment is separately evaluated based on several considerations such as inspection results, impact rating factors, frequency of defects, and engineering and administrative factors. The marks of defects were assigned in such a way that the worst condition has the highest mark. The factors considered by applying marks system were identified from questionnaires that were prepared and distributed by the author to technicians, engineers, heads of departments and managers of municipalities of several cities in Iraq. The case study includes seventeen concrete sewer pipes in the municipality of Al Diwaniyah city – Iraq. CCTV inspection was carried out to determine the marks of the structural and performance defects. Results of marking rating system applied on the seventeen sewer pipes showed that MP#12 has the worst condition with highest marks of 38. Sewer pipes MP#1 and MP#7 have the best condition with lowest marks of 18. The prioritization of rehabilitation should have descending ordered from the highest to lowest mark.