Identification of most significant factors for modeling deterioration of sewer pipes

Existing methods used to identify the important factors that can improve predicting structural deterioration of sewer pipes rarely take into account the interactions and correlations among them. Here we present a standardized method that combines use of the Cox model and likelihood ratio test, and overcomes these limitations of previously employed methods. This combined method is applied to the pipes of two Canadian sewer systems, and its results are compared to the results of two simpler methods for the identification of the factors that significantly influence sewer pipe deterioration. The three methods identified pipe age as the principal factor driving the structural deterioration of sewer pipes. However, slight differences between the methods for other potential influential factors (material, slope and diameter) showed that accounting for the interactions and correlations among factors, as is possible with the proposed method, is crucial to identifying the factors having a significant impact on pipe deterioration.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author