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Assessment of potential impacts of climate change on the integrity and maintenance costs of simply supported steel girder bridges in the United States




Palu, Susan Mayumi Kock, author
Mahmoud, Hussam, advisor
Atadero, Rebecca, committee member
Senior, Bolivar, committee member

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Bridges in America are aging and deteriorating, causing substantial financial strain on federal resources and taxpayers' money. Amid several deterioration issues affecting bridges one of the most common and costly is malfunction and deterioration of expansion joints, due to accumulation of road debris between joints, traffic, and weather. Clogged joints in particular prevent the superstructure from expanding when subject to a temperature increase, giving rise to thermal stresses that are not accounted for during the design phase. These additional demands, in the form of combined axial loads and moments, are expected to even worsen considering potential future changes in climate. Herein, a new framework is developed to assess structural vulnerability and estimate maintenance costs for approximately 80,000 simply supported steel girder bridges across the U.S. The approach aims to aid in establishing a priority order for bridge maintenance and offer insights on how to better allocate funds for a large inventory of bridges. The structural vulnerability is quantified in terms of the reduced capacity resulting from axial load and moment interaction on the girder-slab composite. The projected daily maximum temperatures for future years of 2040, 2060, 2080 and 2100 were processed from the coupled climate model GFDL CM3 under three climate scenarios: RCP 2.6, RCP 6.0 and RCP 8.5. The results showed that the most critical regions for all climate scenarios are: Northern Rockies & Plains, Northwest, Upper Midwest and West. In contrast, the less susceptible regions are the Southeast followed by the Northeast. In addition to vulnerability, life cycle cost analysis was conducted considering the evolution of structural condition of each asset along the years through the interaction equation. The results showed that savings on the order of $4.5 billion could be attained when vulnerability-informed maintenance practice is followed as opposed to its conventional counterpart. It was observed that the climate scenario RCP 2.6, which represents greater efforts to reduce anthropogenic climate change, resulted in the smallest maintenance cost. Moderate efforts over emissions RCP 6.0 implies a $600 million increase, while no intervention under RCP 8.5 results in an additional $2 billion cost over the long term.


2019 Fall.
Includes bibliographical references.

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climate change
infrastructure vulnerability
life cycle cost analysis
expansion joints


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