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Determining the items that structure bridge management components and their relative weights

Date

2012

Authors

Johnson, Joshua F., author
Ozbek, Mehmet Egemen, advisor
Clevenger, Caroline, committee member
Atadero, Rebecca, committee member
Chen, Suren, committee member

Journal Title

Journal ISSN

Volume Title

Abstract

Ensuring the optimal allocation of available resources between competing bridges is difficult, especially when considering a combination of factors such as continual age related deterioration, ever-increasing traffic demands, and limited resources to address preservation and improvement needs. Optimally allocating funding is crucial since bridges are an essential and expensive component of transportation networks. Bridge Management Systems (BMSs) are commonly used tools that aid managers and decision makers in establishing methods for optimizing available resources and determining how to distribute funds between competing bridges. Recently, NCHRP Synthesis 397 Bridge Management Systems for Transportation Agency Decision Making investigated how transportation agencies are using BMSs and the current state of bridge management practices. The report identified concerns of inadequacy and ineffectiveness with bridge management practices that base decisions solely on single value assessments such as Pontis' Bridge Health Index or the Sufficiency Rating, as found in the federally mandated National Bridge Inspection Standards. Given the critiques in the NCHRP report and other literature related to bridge management, it is evident there exists a need to pursue and develop alternative bridge management practices and systems. The overall purpose of this research is to investigate the concept of isolating the items used to make up a single rating or index in an effort to categorize them under distinct bridge management components such as structural condition, impact on public, and hazard resistance. Each bridge management component has a defined objective as follows: • Structural Condition - accurately access the structural adequacy of a bridge. • Impact on Public - evaluate how bridge attributes affect the traveling public. • Hazard Resistance - evaluate how bridge attributes and external factors affect the vulnerability of a bridge concerning the probability of an extreme event as well as the probability of failure during that event. The specific objectives of this research are (i) to identify the appropriate items that make up each of the aforementioned components and (ii) to determine the relative importance of those items as represented by weighting factors. To achieve these objectives, the researcher conducted a two-part survey seeking input from key bridge management personnel from State DOTs, the Federal Highway Administration (FHWA), and other industry professionals and experts. The first part of the survey identified the appropriate items and the second part determined the relative importance of those items using a mathematical method called the Analytic Hierarchy Process (AHP). The primary contribution of this research is to provide bridge management engineers and decision-makers with effective bridge management components, with well-defined objectives and related items, which clearly identify and distinguish differences in bridge attributes that may go unnoticed when using a single rating or index. This will especially be useful for State DOTs and local agencies, like the Wyoming Department of Transportation, from which the motivation for this research was adapted, who are developing BMSs and methods customized to their particular needs. Upon establishing the bridge management components, by determining the items that make up the components and their relative weights, transportation agencies may utilize them in a variety of ways to conduct multi-criteria decision analyses that complement their current bridge management practices, which in turn may better illustrate the operation of bridges in their system. The total number of respondents was 47, of which 32 were from 29 different State transportation agencies. Of the 47 participants, only 27 contributed to the second part of the survey. A major finding of this research was a result of several participant remarks about with quantifying preservation and maintenance demands through the addition of a fourth bridge management component. The preservation and maintenance component encompasses items that are bridge elements, but may not contribute to the structural capacity of a bridge. Given the degree of influence of adding a fourth component, further research is recommend to confirm these findings and conclusions with a refined two-part survey similar to this research study and possibly interviews or focus groups.

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Subject

analytic hierarchy process
bridges
decision-making
multi-objective
optimization
preservation

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