The AASHTO Standard Specifications for Highway Bridges (14th Edition, 1989) are used for the design of highway bridges by many public and private agencies in the United States and abroad. Sections 4, 5, and 7 of Division I---Design, provide guidance for the design of highway bridge foundations, retaining walls, and substuctures.

The objective of this project was to develop recommended revisions to Sections 4, 5, and 7 of the AASHTO Standard Specifications for Highway Bridges to reflect the current practice and state of the art in geotechnical engineering and substructure design.

The project was completed and the recommended specifications and commentary were submitted to AASHTO in 1989. The recommended specifications provided a complete re-write of Sections 4, 5, and 7 to the design specifications. AASHTO adopted the revised specifications and commentary in 1990, and they were subsequently issued with the 1991 Interims to the Standard Specifications for Highway Bridges.