This paper presents a simplified approach for the evaluation and ranking of alternative construction methods that can be employed in the installation, rehabilitation or replacement of buried sewer pipes. Rather than developing a new approach, the model adopts selected features from existing approaches and combines them into a single, generic and easy to codify algorithm. The approach selected emphasizes simplicity and practicality, and limits input data to those readily available to municipal engineers. Based on the specific characteristics of the problem(s) facing the decision-maker, a generic flow chart is used for preliminary screening. In most cases, a number of construction methods listed in the database will have the capacity to address the problem(s) under consideration. A technical evaluation is then undertaken during which the technical capabilities (e.g., drive length) of the various technologies identified in the first step are compared with the project's attributes. A risk analysis is performed based on the characteristics of the project's environment and the anticipated subsurface conditions. Technologies that successfully pass the above-described evaluation are then ranked based on preference attributes that include duration, cost and environmental impact. The analysis is repeated for each segment of the pipeline under consideration. Finally, an optimization procedure is undertaken based on unit costs, mobilization costs and local availability to identify the technology or combination of technologies that satisfy the user's requirements in the most economical manner. The model is codified in Visual Basic.Net, an object oriented programming language, that offers an interactive graphical user interface.
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