Probabilistic Seismic Vulnerability Assessment of Tall Horizontally Curved Concrete Bridges in California

Abstract

The seismic performance of bridge structures is significantly affected by their column height, design era, and horizontal deck curvature. However, existing risk assessment platforms do not appropriately account for the effect of column height and horizontal deck curvature. This paper investigates the effect of column height, design era, and deck curvature on probabilistic seismic demand models and fragilities of bridges. This paper selects a typical configuration of horizontally curved concrete box-girder bridges in California: two-frame five-span bridges with single-column bents. Extensive nonlinear time history analysis results for the bridges including the uncertainties are initially compared using a statistical technique, analysis of covariance. Results from the analysis of covariance are used to estimate the influence of column height, design era, and horizontal deck curvature on bridge performance. An increase in the deck horizontal curvature is found to increase the bridge vulnerability irrespective of the design era and height range. Although the seismic vulnerability of bridges constructed prior to 1970 increases with the increase in the column height, there is no specific trend in the change in vulnerability with respect to column height for bridges constructed after 1970. This research also shows that the implementation of seismic design principles reduces the seismic vulnerability of the bridges.