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Resiliency framework for long span bridges to extreme loads

This study presents a framework for quantitative measure and mathematically reproducible definitions of structural resiliency as it pertains to a bridge's ability to minimize the potential for undesirable consequences. The resiliency assessment and design process follows logical progression of steps, starting with the characterization of hazards, continuing through analysis simulations, damage modeling and loss assessment by finding and subsequently balancing functional relationships between design, analysis, damages and consequences. The outcomes of each process are articulated through a series of generalized variables, termed as Topology, Geometry and Hazard functions. Topology is a quantitative function establishing relationship between bridge structure and hazard characteristics, such as type of hazard and location of hazard. Geometry is a quantitative function establishing relationship between localized damage and consequences due to this damage. Hazard magnitude is a quantitative measure of the hazard magnitude that structure is subjected to. In this paper we demonstrate that quantitative measure of structural robustness can be estimated by integration of Topology and Geometry functions. The resiliency of a structure can be estimated by integration of Robustness and Hazard functions. A rigorous probabilistic framework permits consistent characterization of the inherent uncertainties through the process. The proposed framework is well suited for design process through stochastic characterization of assessment measures. Through stepwise approach, the framework facilitates a system wide approach to multi-hazard threats by establishing functional relationships between the development of appropriate models, design methods, damage acceptance criteria and tools necessary for implementation. The proposed methodology can be implemented directly for performance assessment, or can be used to as a basis for establishing simpler performance criteria and provisions to achieve resilient structural solutions. The application of the process is demonstrated through assessment of example cable stayed bridge.

Author(s):

Shalva Marjanishvili    
Hinman Consulting Engineers, Inc
United States