For many years, engineers have designed foundations, walls and culverts for highway and other applications using allowable stress design (ASD) methods. In ASD, all uncertainty in loads and material resistance is combined in a factor of safety or allowable stress. For most highway design, the American Association of State Highway and Transportation Officials (AASHTO) Standard Specifications for Highway Bridges represents the primary source document for ASD of substructures. In 1994, AASHTO approved Load and Resistance Factor Design (LRFD) in the LRFD Highway Bridge Design Specifications. In LRFD, the uncertainty in load is represented by a load factor and the uncertainty in material resistance is represented by a resistance factor. Due to the fundamental differences between the substructure design process by ASD and LRFD, this course has been developed to present the fundamentals of LRFD for the geotechnical design of highway bridge substructures....More >< Less