Full Description

In Europe, rehabilitation policies for drinking water pipes are based on criteriacloser to budgetary restrictions than to an authentic technicoeconomicconsideration. In this reactive approach, the only rehabilitated pipes are thosewhich have failed or have been repaired at more than a subjective rate. Thisapproach brings about a very low rehabilitation rate and a proactive approachwould be more advantageous. This paper presents different models and methodsadapted to such a proactive approach. These models were created in differentEuropean research centers and universities. They can be classified into two majortypes according to their objectives: models assessing the structural state of thepipes based on statistical methods; and, models assessing and comparing therehabilitation strategies, based on technical and economic assumptions. The firsttype of models use short- or long-term data maintenance records and consist oftwo stages. The first stage includes an analysis of the influencing factors.These factors are either specific factors such as material and diameter orenvironmental factors such as soil, traffic or location of the pipes. Secondly,the state of the pipe is assessed or forecasted using specific models, such asPoisson or Weibull models. They end in classifying pipes either in groups or pipeby pipe. The second type of model requires a description of the network (age,length, material and failure rate) and integrates some economic data. Previousstudies on European cases are used to classify data requirements. For each model,the authors define "required data", "highly significant data" and "useful data".Previous results are provided as an illustration. In the second part of thepaper, case studies are presented dealing with available data in Europeanservices. It shows that available databases remain incomplete regarding failureanalysis and modeling, and rehabilitation forecasting. Includes 11 references, tables, figure.

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Edition: Vol. - No. Published: 01/01/2000 Number of Pages: 12File Size: 1 file , 260 KB