Statistical Analysis of Fragility Curves

Keywords: Fragility curves.  Bridges.  Seismic performance.  Nonlinear dynamic analysis.  Parameter estimation.  Highways.  Expressways.

Abstract: This report applies both empirical and analytical fragility curves to present methods of bridge fragility curve development.  The empirical data utilizes damage obtained from past earthquakes including Northridge and Kobe; analytical samples use nonlinear dynamic analysis and are constructed for typical bridges in the Memphis, Tennessee area.  Two-parameter lognormal distribution functions are used to represent the fragility curves.  This report also introduces statistical procedures for testing goodness of fit of the fragility curves and for estimating the confidence intervals of the fragility parameters.  Additionally, exploratory research was conducted to compare these two fragility curves with those constructed utilizing the nonlinear static method.  The conceptual and theoretical treatment addressed in this report is intended to provide both a theoretical basis and practical, analytical tools for the development of fragility curves and their application in the assessment of seismic performance of expressway network systems.  Figures and tables are used extensively throughout the report.