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Developments in Deep Foundation Highway Practice - The Last Quarter Century

DiMaggio, Jerry A. / Goble, George G.

This paper examines the many significant changes in deep foundation design and construction, within the United States highway practice, during the last quarter century. The impressive listing of advancements has resulted in numerous benefits to the professional community, the deep foundation industry, and to United States taxpayers as well as private owners. The benefits have been tangible and intangible, and include reduced total project cost, accelerated speed of construction, development and deployment of improved materials and construction equipment, improved specifications and contracting procedures, and an overall improved appreciation of Geotechnical Engineering within the highway industry. Based on the authors' more than 30 years of experience, in depth comparisons are made between current practice, national practice circa 1980, and 20 years in the future (2023). The information provided is partially obtained from the Federal Highway Administration's (FHWA) Geotechnical Program Review series that has been used by FHWA's National Geotechnical Team (NGT) to benchmark and assess Geotechnical Engineering highway practice since the early 1970s. Unfortunately, not all the developments have been positive nor have all the important and necessary changes that should have taken place occurred. This paper examines these topics by following an overall suggested development and delivery flowchart for deep foundation projects. An overall suggested design and construction process is presented with emphasis on several keys steps that are sometimes omitted or misapplied on even major projects.