Development of a Pavement Management Model at the Project Level by Analytical Hierarchy Process (AHP)

To develop an optimal pavement management system, several factors such as economic indices, improved utilization parameters, improvement in structural situation of pavements and the effect of options on the environment, social and safety measures, etc…. should be considered. Inputting the above mentioned parameters into the priority chain of the determined options, requires a multi disciplinary decision making process. In this paper, a model on the basis of Analytical Hierarchy Process has been developed.In order to evaluate the technical and economic aspects of the model's options, first of all the input data required for Elmod-5 and HDM-4 programs is prepared. Prioritization of repair and maintenance options and finally decision making for determination of the preferred option is done by AHP and Expert Choice Software, using the results obtained from implementation of the model.The pavement management system is usually practiced in two network and project levels. In the pavement management at the network level, the priority of projects and the operations regarding their maintenance and time schedule is determined by the present limitations, while in the project level, the implementation of various methods of repair and maintenance for a specific project is evaluated and compared.In this research a model has been designed for the pavement management in which by using the Life Cycle Cost Analysis and the AHP, the prioritization of options and decision making about the pavement management is improved. The construction phases of the MPHS Model are as follows:- Supply of input data- Preliminary evaluation and segmentation of pavement- The preliminary selection of repair and maintenance options- Techno economic evaluation of options- Prioritization of options- Choice of maintenance method- The HDM–4 and ELMOD-5 software have been used for techno economic evaluation of the various options. The analytical framework of the HDM-4 Model is based on the Pavement Life Cycle Cost Analysis. This model is used for prediction of factors such as road destruction and ageing, effects of the road situation on utilization, effects of the road users, and finally environmental, technical and economic effects on the life cycle of a pavement which is usually 15-40 years. In the new model, on the basis of comprehensive literature review as well as the experiences of experts (direct interview), the most important factors for techno economic evaluation of options were selected. These factors include economic parameters, the comfort of vehicle's users, the structural stability and the drainage quality.In this research, the Western – Eastern route of Shahid Babaiee Expressway in Tehran was chosen as the case study and the pavement life cycle analysis for a period of twenty years was implemented.Using this model, the decision makers can choose the most suitable and optimal way for the improved management of pavements through changing the weight of decision measurements and recognition of the expert's experiences and viewpoints, using the group AHP Method.This study is illustrative of the fact that the criteria of "economic output" is the most important parameter affecting the repair and maintenance choice and then some other parameters like the comfort of the vehicles attendants, the quality of drainage and the structural stability are accordingly the other important parameters in decision making process. Therefore, none of the above mentioned factors can merely be the suitable criterion for the prioritization of options and the choice of the suitable maintenance method.