Behavior of box culvert with geofoam as a backfill material in Highway

Abstract

Box culverts are generally required to provide a passage for drainage and small vehicle and act as a stable base for a road embankment. Box culverts are subjected to traffic load and overburden pressure due to the cushion. Mostly box culverts are subjected to the lateral earth pressure and overburden pressure. The quantities of reinforced concrete in box culvert depends upon the anticipated lateral earth pressure which may be larger than overburden pressure. The magnitude of earth pressure due to a large quantity of backfill generates stresses and deformations on the face of box culvert. For counteracting this large pressure, either more thickness of reinforced concrete in box culvert is provided or light weight material is used as a backfill. EPS geofoam is a light weight backfill material which reduces the dead and lateral load on box culvert. The objective of this paper is to optimize the thickness of box culvert with the use of EPS geofoam as backfill material. For achieving this objective, finite element analysis has been done using PLAXIS 3D. The results of finite element analysis shows that the inclusion of geofoam as backfill material helps in reducing lateral deformation at the face of box culvert as compared to conventional backfill material. The use of geofoam makes it possible to reduce the thickness of box culvert which is beneficial in minimizing concrete requirement therefore reducing total cost of project.