The management of bridges as a key element in transportation infrastructure has become a major concern due to increasing traffic volumes, deterioration of bridges and well-publicised bridge failures. Identification of the nature of deterioration and appropriate remediation treatments remains a complex task. A critical responsibility for asset managers in charge of bridge remediation is to identify risks and assess the conditions to ensure that remediation decisions are transparent and lead to the lowest predicted loss in pre-determined constraint areas. Bridge management agencies have traditionally made decisions based on a subjective judgment using organisational rules of thumb. Lack of a generic method for quantifying the overall condition of bridges (following inspection) is one of the major issues. Moreover most existing models deal separately with network level and project level problems. This thesis demonstrates that the subjective nature of decision making in bridge remediation could be replaced by the application of Decision Support System (DSS) as a tool for assisting decision makers to deal with an extensive spectrum of problems. The main goal of this research is to develop a requirementsdriven decision support methodology for remediation of concrete bridges with the aim of maintaining bridge assets within acceptable limits of safety, serviceability and sustainability. In this study a quantitative methodology has been developed and illustrated to give insights for decision makers to select the best bridge management strategy. The methodology includes two phases with different steps in each phase:
Phase one is focused on condition assessment and priority ranking of bridge projects which makes use of an integrated priority index addressing the structural and functional efficiency of bridge, taking into account the clients’ preferences. Phase two includes a multi criteria decision making technique which is able to select the best remediation strategy at both project and network level. The modified Simple Multi Attribute Rating Technique (SMART) is used as a decision analysis tool that employs the eigenvector approach of the Analytical Hierarchy Process (AHP) for criteria weighting. A method for selection of the best remediation plan in terms of fund allocation for top ranked bridges of the network is also proposed using the outputs of the previous procedures considering the budget as the main constraint.
The model proposed in this thesis introduced as CBR-DSS has significant benefits over the currently used methods. The thesis clearly shows that the developed model is able to add more objectivity and holism to the current approaches through considering the main aspects of the problem and attempting to quantify the major parameters. CBR-DSS is also flexible enough to allow decision makers to engage their judgments in the decision making process. It can handle multi layer of data and multi criteria decision problems and is able to combine the project and network levels of the bridge management process.
Available at: http://works.bepress.com/maria-rashidi/10/