Settlement of strip footings on a strong cohesionless layer overlying a weak deposit

In foundations and road engineering, it is quite often to encounter ground made of deep weak deposits. Structures built on this ground will experience low bearing capacity and excessive settlements. As an alternative to deep foundations and/or expensive soil improvement operation, especially in the case of highways and roads, replacing a limited thickness of this material by strong granular layer will increase the bearing capacity and reduce the settlements of these structures significantly.; The purpose of this study is to determine the reduction of the settlement of a strip footing on a weak deposit as a result of replacing the top layer immediately below the footing with a strong granular material. The parameters to be considered in this analysis are the initial strengths of the weak deposits as well as the artificially added top layer, the thickness of the top layer, width and depth of the footing, and level of loading.; The analysis will be conducted by means of finite element technique using the program CRISP which was developed by Cambridge University. The results are presented in the form of a parametric study to determine the effect of each of the above mentioned parameters on the settlement of these footings, and to determine the settlement components of the upper and lower layers and to establish the role of the upper layer to reduce the total settlement of these footings. A design chart will be presented to assist the practicing engineers in determining the contribution of the artificially added top layer in reducing the settlement of these footings.