Propagation and quantification of uncertainty in the vulnerability estimation of tall concrete bridges

Abstract

Bridges are critical links in a transportation network, and their seismic vulnerability can lead to substantial economic losses, particularly the ones located in high-risk seismic zones. Bridge vulnerability can be assessed by developing fragility curves that indicate the probability of reaching or exceeding a specific level of damage. Past earthquakes have revealed a high likelihood to experience seismic damage for bridges with irregularities in their configurations. Since the research on the seismic reliability of irregular bridges with consideration of uncertainty is limited, this paper aims to address this deficiency by analyzing the impacts of typical sources of uncertainties including ground motion, material, and geometric attributes on the vulnerability of tall and normal box-girder concrete bridges. This study compares the fragility of considered cases by performing nonlinear time history analysis of representative bridges and developing probabilistic seismic demand models in order to generate the corresponding fragility curves. During this process, the influence of each type of uncertainty is investigated through statistical analysis of the bridge responses. The findings demonstrate a noticeable seismic risk of tall bridges compared to the normal ones, and among the evaluated categories, the uncertainties associated with the geometric attributes showed the highest influence on the seismic demands.