Lateral deformation of bridge embankments supported on soft soils

Excessive bridge embankment deformation, namely in the lateral direction, continues to damage bridges leading to costly repairs or early replacement. The lateral deformation of bridge embankments is often overlooked in routine analysis due the complex nature of the deformation. The goal of this research was to better understand the relationships between embankment geometry, foundation soil variables such as strength and permeability, and the lateral deformation an embankment will experience. To support this research an advanced constitutive model was implemented into the commercial finite element software PLAXIS 2D allowing for realistic embankment deformation predictions. Several instrumented embankments were modeled to verify the constitutive model’s prediction abilities. In addition, SH 3 over BNSF railroad in Ada, Oklahoma was investigated and modeled as a case study to support this research. A parametric study was then performed for bridge embankments with piles. In the parametric study the embankment foreslope (slope facing the bridge), embankment height, foundation soil thickness, foundation soil strength, and the foundation soil permeability were systematically varied. Recommendations for minimizing the potential lateral deformation bridge embankments founded on soft soils will experience were developed based on the results of the case study and parametric study