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Reduction of road closure times, traffic disruption and user costs, in addition to improvements in construction quality utilizing prefabricated elements, are all attractive qualities of the implementation of ABC techniques that encourage the transportation agencies to use the technique for repair and replacement projects. However, despite the extensive developments in effective design and construction of the ABC bridges, there are limited guidelines in planning phases for selection of the candidate bridges and the appropriate construction technique. A cursory review of the literature shows that there are two major decision strategies for prioritization of the bridges for ABC: the Analytic hierarchy process (AHP) and the two-stage decision making tool followed by the Iowa DOT that integrated AHP in the second stage of the decision making process. These decision processes use readily available data from NBI (such as AADT, out-of-distance travel, and daily user costs) to qualitatively rate the bridges, then if a bridge is considered as a candidate for the ABC, the AHP method is used to qualitatively compare the options based on factors such as construction schedule, direct and indirect costs, and site constraints. This highlights the need for a holistic decision making algorithm that integrates the project-level parameters (such as the project completion time, site conditions, availability of specific resources, etc.) into an enterprise-level asset management framework (such as the effect of project in the region, accessibility and connectivity to critical facilities, the economic growth of the region, social return on investment, etc.). This is in addition to the need for a holistic framework that would be readily available in case of emergency conditions when there are multiple bridges affected by a regional natural hazard that would require immediate prioritization based on such factors as importance to the connectivity and accessibility of the network.
The main objectives of the proposed project are as two folds:
- Development of an enterprise-level decision making framework by simulating the transportation network of the region under consideration, definition of the performance measures, identification of critical facilities, social effects, economic impact to business/industrial districts in the region for prioritization and ranking of the ABC bridge candidates
- Development of a matrix-based project-level decision framework consisting of important indices (such as time, cost, or safety) that affect the outcome of the project in terms of time and constructability
The final outcome of the two tiers will be a holistic decision making framework that not only considers the project level factors in choice of ABC techniques but also goes beyond the physical borders of a specific project and considers the regional effects that a specific bridge could have in the everyday life and long term growth of the region.
To develop a holistic decision making framework for selecting the candidates for ABC techniques, a multi-level optimization scheme that covers from project- to enterprise levels is required. The research here will have specific focus on the operational applications (such as the use of ABC for repair and replacement of deficient or obsolete bridges) as well as extreme event applications (specifically when a large number of bridges are affected by regional hazards such as floods, hazards, and hurricanes). To achieve the goals of the project, three major steps will be taken: i) A multi-level decision making framework covering scales from project- to enterprise-level will be developed, ii) the framework will be implemented for the state of Iowa bridges as a test-bed and its effectiveness in operational conditions will be evaluated, and iii) the application of framework will be extended for use as a decision making tool for post-event emergency response to an extreme event affecting a region.
The following tasks will be performed to achieve the project goals:
- Task 1 – Literature Review
- Task 2 – Network-Level Planning Framework for Ranking and Prioritization
- Task 3 – Project-Level Framework for Best Construction Method Approach
- Task 4 – Application to the Test-Bed and Comparison with Previous ABC Projects
- Task 5 – Final Report
Principal Investigators: Dr. Alice Alipour and Dr. Doug Gransberg
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