Development of empirical fragility curves for bridges

This paper presents the methods used in analyzing bridge damage and repair cost data from the Loma Prieta and the Northridge earthquakes. Such data, however, have not been systematically studied with the objective to evaluate damage characteristics and to correlate these earthquake ground motions. Logistic regression analyses are used to determine the structural characteristics most correlated with the observed damage. Bridges are grouped by these structural characteristics and empirical fragility curves are developed for these groups of bridges. The method for developing empirical fragility curves and examples are presented.