Generalized assessment of bridge vulnerability to terrorist threats: a probabilistic structural analysis based approach
Date
2006
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Publisher
University of Delaware
Abstract
Recent events, including the attacks of September 11, 2001, have brought into light the need to understand and assess the vulnerability of civil infrastructure systems to terrorist threats. The vulnerability of the nation's transportation infrastructure is of particular concern to the public, planners, and administrators. An attack on a strategic link such as critical bridge has the potential to cause substantial casualties, economic disruption, and social changes. While infrastructure vulnerability is widely acknowledged, it is not feasible to fortify, protect, or otherwise eliminate the threats posed to the entire transportation infrastructure. Thus, infrastructure owners must make decisions regarding how to best distribute their limited resources across their inventories. The overall objective of this thesis is to provide guidance to transportation infrastructure (specifically bridge) owners who must make these important decisions. ☐ This thesis begins with a discussion of the state-of-the-art and a critique of existing literature. Subsequently, this thesis presents a rational methodology for assessing the vulnerability of bridges to terrorist attacks. The methodology involves a probabilistic structural analysis based approach that seeks to fill several voids in the existing literature. However, analysis of both the structural response of bridges to terrorist attacks and the myriad of associated consequences are rapidly evolving fields. To account for the changes in this growing field the methodology is non-prescriptive and remains adaptable to account for advancements. ☐ Additionally, this thesis presents three illustrative case studies that include analyses of structural response and damage consequences besides addressing broader issues associated with actual assessment of inventories. The first case study involves a bare-bones analysis of a cable-stayed bridge subject to an attack. The second case study involves a highway bridge. It presents a detailed example of how an analyst can utilize first principles based analyses (using custom made computer codes for Monte Carlo simulation, blast pressure modeling and structural dynamics analysis) to increase efficiency and flexibility in applying the methodology. The third case study illustrates how commercial finite element software can be employed when assessing structural response of bridges to blast events. Suggestions for future research are presented throughout.