Duchesne S.,Eau Terre Environnement Research Center |
Beardsell G.,Eau Terre Environnement Research Center |
Villeneuve J.-P.,Eau Terre Environnement Research Center |
Toumbou B.,Eau Terre Environnement Research Center |
Bouchard K.,Eau Terre Environnement Research Center
Computer-Aided Civil and Infrastructure Engineering | Year: 2013
The structural state of sewer systems is often quantified using condition classes. The classes are based on the severity of structural defects observed on individual pipes withthe system. Here, a survival analysis model was developed to predict the overall structural state of a sewer network based on camera inspection data from a sample of pipes the system. The convolution product was used to define the survival functions for cumulative staying times each condition class. An original calibration procedure for the sewer deterioration model was developed to overcome the censored nature of data (left censored and right censored) available for the calibration of sewer deterioration models. The exponential and Weibull functions were used to represent the distribution of waiting times each deterioration state. Cross-validation tests showed that the Weibull function led to greater uncertainty than the exponential function for the simulated proportion of pipes that are a deteriorated state. Using various sample sizes for model calibration, these cross-validation tests also showed that the model's results are robust to smaller calibration sample sizes. This confirms the model's potential for predicting the overall state of deterioration of a sewer network when only a small proportion of the pipes have been inspected. © 2012 Computer-Aided Civil and Infrastructure Engineering.