Numerical simulations for response of MSE wall-supported bridge abutments to vertical load

In recent years, mechanically stabilized earth (MSE) walls have been proposed as support for bridge abutments on shallow foundations due to significant cost savings over conventional pile-supported designs. This paper presents new research on numerical modeling of a realistic MSE wall-supported bridge abutment using the finite difference program FLAC-2D. MSE abutments are typically subjected to much larger loads from bridge superstructures than conventional MSE walls. An MSE bridge abutment with a flexible wall facing is a complex system that includes granular backfill, reinforcement, concrete facing blocks, and a shallow foundation for the abutment structure. In the numerical simulations, soil-block, block-block, and soil-abutment interactions were simulated using interface elements, and soil-geogrid interactions were simulated using cable elements. The MSE abutment is subjected to a vertical bridge load of 200 kPa. Results are presented for static conditions and include lower wall facing displacements, abutment structure settlements, maximum tensile forces in the reinforcement, lateral earth pressures, and vertical stresses under the abutment structure and at the soil foundation level. The numerical results are discussed with regard to practical field applications.