NEW MANHOLE CONDITION PRIORITIZATION TOOL PRODUCES EFFICIENT AND ROBUST ANALYSIS OPTIONS

The wastewater industry has focused considerable effort on the standardization of defect codes. Less attention, however, has been given to the mathematical and scientific principles of aggregating similar and differing defects to produce asset condition scores and comparative ratings that improve the value of the condition data collected. This is the case for sewers and particularly for manholes.Defects can be used to describe the physical state of a pipe or manhole structure in a dynamic surrounding environment. Defect data are often complex. Traditional defect scoring approaches extract only portions of the collected data and oversimplify the scoring process. A robust scientific scoring process considers the full value of all the collected data and provides a more reliable analysis. The authors determined that a condition prioritization tool was needed that retained thedetailed status of the defect, but at the same time, communicated the results in a simple form commonly portrayed in tables, graphs, and capital improvement planning reports.The paper describes the concepts and efficiencies of a new tool developed by the authors called SCREAM™ Manhole Condition. The SCREAM™ methodology was developed to assign condition assessment scores to multiple manhole components and to assign scores on a vertical location basis, such as upper and lower levels, to facilitate cost-effective analysis.Manhole scores are calculated automatically for structural, maintenance, and infiltration/inflow (I'I) conditions. The combination of these three conditions produces a total of 12 different performance groups, considering both the upper and lower levels of the manhole. This paper demonstrates how these scoring options provide ranking flexibility to sequence subsequent maintenance or repair, replacement, or retirement activities. This method also will be compared with otherindustry manhole condition ranking methods.