Geogrid is made of a polymer and as a stiffener layer in soil to be used and increase capacity and reduce lateral displacement of the wall and the sill settelment follow. In recent years, put bridge deck by a strip foundation on the abutment was used as a efficient method of building bridges has been was introduced. with this method besides being economical and high-speed performance, bump due sill dissimilar between abutment and pile foundations will be eliminated. studies show increase geogrid width to reduce the lateral displacement of the wall is effective. in this paper influence pressure and width sill on the optimal width of geogrid was investigated. also with considering the maximum allowable displacement of the wall sort appropriate geogrid was investigated until the most economical mode that provide stable and displacement of the wall does not exceed the limit set by the regulation is achieved. depth placement the first geogrid under sill in reduction settlement sill is effective so with placement gegrid at different depths the optimum depth is research. in this study 3D analysis by software Abaqus-V6.11-1 with Cap plasticity models done.