Factors Contributing to Bridge–Embankment Interaction

Abstract

Seismic analyses typically neglect four important phenomena that contribute to the complex interaction between bridges and approach embankments: three-dimensional embankment response, nonlinear soil behavior, soil–structure interaction, and embankment scattering. To identify the importance of each phenomena, a modeling approach was adopted that can be implemented with commonly available soil and structure properties, and whose computational demands are sufficiently low to perform numerous dynamic analyses. The accuracy of the methodology was established by comparing measured and computed abutment acceleration response histories, response spectra, structural periods, damping ratios, and abutment stiffnesses for several bridges. Parametric studies indicated that, to maintain accuracy over a range of earthquake intensities, it is important to consider three-dimensional embankment effects and to specify soil properties accurately. In contrast, the computed response was nearly insensitive to the effects of embankment scattering and changes in embankment geometry, including the embankment height.