Highway approach embankments are often constructed over weak and compressible soils. The consolidation settlements induced by the embankment loads are known to result in downdrag forces and lateral forces on the piles supporting the bridge abutments. Several approaches are commonly employed during construction of highway bridges in Ontario in order to reduce these forces. These approaches include: preloading and surcharging to achieve the anticipated settlements prior to the installation of abutment piles; application of lightweight fill materials such as expanded polystyrene and expanded pelletized blast furnace to reduce embankment loads; and measures to expedite pore water pressure dissipation such as wick drains. This paper presents a case history where the abutments of seven bridges on the Macdonald-Cartier Freeway between Carnwall and the Quebec border experienced excessive movements, which resulted in extensive repair work in three of these structures. A series of numerical analyses are conducted to provide an explanation for abutment movements in Brookdale Avenue underpass structure. Two-dimensional nonlinear finite element analyses were conducted using commercial software package, PLAXIS 2D to evaluate the forces and moments acting on the abutments as a result of embankment loading. The behavior of compressible soils is modeled using Soft Soil Model (SSM). The results indicated that the consolidation settlements and their impact on the abutment piles were estimated with an acceptable accuracy using FE model. The results presented in this study are considered to be of interest to researchers and practitioners
