Le « goal programming » pour l'optimisation de la planification de la réhabilitation des réseaux d'égout.

Sewer rehabilitation planning is a complex problem that needs the development of some tools that facilitate the integration of many factors and parameters influencing the status of sewer pipes. Generally only the structural aspects are considered in the rehabilitation planning and sewer degradation studies. Some studies that integrate the hydraulic performance do not consider the real responsibility of each pipe in the surcharges or they only introduce a prioritization without considering the economic factors or the suitable rehabilitation method to use. In this study, an integration of two aspects (structural and hydraulic) of the performance of sewer pipes is considered and the planning over a time horizon is presented. The proposed methodology selects the suitable rehabilitation method for each sewer pipe in order to minimize the overall deviation from the desired structural and hydraulic performance levels within a limited budget. The methodology requires, on one hand, the standard structural classification of the pipes, which is considered in the computation of the initial structural performance. On the other hand, the global hydraulic performance of each conduit is calculated by computing the runoff flows at its entry. These flows are then considered to evaluate the real capacity of the pipes as well as their corresponding performance indexes. An optimisation model is then developed in order to determine the suitable rehabilitation method for each pipe that permits to approach the desired hydraulic and structural performance of the system without exceeding the maximum budget. The methodology has been tested on a sewer of the sector 1 in Verdun, a district of Montreal. The results show the applicability of the methodology and its success. [ABSTRACT FROM AUTHOR]