Investigation of bridge abutment displacements constructed on piles and geogrid reinforced soil using the finite element method

Authors

1 Civil Engineering Department, University of Zanjan

2 Civil engineering, University of Tabriz

3 Road, Housing & Urban Development Research Center, Tehran

Abstract

One of the major problems in highway and railway bridges is the settlement of the bridge abutments, which its reduction has always been set as the research target. Two methods which have been widely used for controlling the settlement are either reinforcing the abutment subsoil with geogrid orconstructing the abutments on piles. This paper describes the application of a two-dimensional finite element method (FEM) by using Plaxis2D V8.5 for comparing the performance of these two methods. The effect of the geogrid normal stiffness, length and depth of reinforcement on the horizontal and vertical displacement of abutment is also investigated. Data from an instrumented bridge abutment has been used for the model verification. The reduction of the bridge abutment,the vertical settlement and the horizontal displacement by pile and geogrid have been analysed and compared.It is found that constructing the abutment on piles has a better performance in reducing the vertical settlement of the bridge abutment. However, lower lateral displacement can be obtained by using a geogrid with a higher normal stiffness. It is also found that, while the vertical settlement is not affected by the geogrid stiffness, the horizontal displacement of the abutment decreases with increasing the stiffness.

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