DFI Traveling Lecturer
The DFI Traveling Lecturer is a prominent industry expert selected annually to travel and present a series of lectures to university students, professional groups and industry associations. The program promotes the field of geotechnical engineering and deep foundation construction by encouraging students to explore a career in the deep foundations industry, providing information on topics of interest to members of the industry, and raising awareness of how DFI and its activities support the industry. The lecture series runs from September 1 – August 31.
The 2023-2024 DFI Traveling Lecturer
Jesús E. Gómez, Ph.D., P.E., D.GE
Jesús Gómez, vice president, GEI Consultants, has over 35 years of design and construction experience in geotechnical projects nationally and internationally. He has led numerous foundation, dam rehabilitation, and earth support projects where he has developed cost-effective, constructible solutions. Gómez obtained a civil engineering degree at Universidad Católica in Caracas, Venezuela, and a Ph.D. in civil engineering from Virginia Tech. He has authored over 80 publications on a variety of geotechnical and structural topics, and on soil-structure interaction. He has been teaching courses on soil mechanics, foundation design, ground improvement and ground stabilization since 1985 as an adjunct professor at various universities, and as an instructor for the National Highway Institute (NHI) and other entities throughout the Americas and Europe.
2023-2024 Traveling Lecture Series Topics
THE L-2 VIADUCT NO 1, VENEZUELA
Viaduct No. 1, on what is formally known as the L-2 highway in Venezuela, was originally built in the 1950s as part of the construction of a vital highway linking the capital city of Caracas with the country’s most important maritime port. By the late 1980s the viaduct was experiencing severe movements, which were found to be product of lateral thrust from a re-activated macro-landslide on its southern abutment, which is likely associated with an active fault zone crossing the viaduct.
The study of the macro-landslide and repeated attempts to mitigate it over two decades became a dominant topic of geotechnical forums in the country. Ultimately, the macro-landslide won, the battle ending with the dramatic collapse of the original viaduct. A replacement viaduct, much longer to bypass the unstable area, was built in record time, with significant construction time savings afforded by the utilization of high-capacity micropiles. This was the first utilization of high-capacity micropiles in Venezuela. It may have also been the first case of large-scale and exclusive utilization of micropiles for foundation of a viaduct of this size in Latin America.
This presentation generally discusses the geotechnical history of Viaduct No. 1 until its collapse and explores its significance within the social framework and the impact of its closure on the economy and the people. More specifically, the presentation covers the micropile foundation design and construction, including details of the micropile design to support the significant compressive and tensile axial loading, shear, and bending product of the substantial seismic motions in the area. The presentation also covers the challenges encountered, such as presenting a new technical concept for an extremely sensitive project, the extremely difficult site and access, poor availability of material and equipment, and political and social pressure behind the project.
EXPLORATION, DESIGN AND QA/QC FOR RIGID INCLUSION PROJECTS
Rigid inclusions are widely used for foundation of a variety of structures and facilities, ranging from mixed-use developments to large industrial and navigation facilities. The most common rigid inclusion type is installed using a displacement-auger following a triangular or rectangular pattern. The elements are capped with a load transfer platform (LTP), which may consist of granular compacted material, although enhanced site soils may also be used. The LTP provides bearing capacity to the spread footings of the structure, while the rigid inclusions provide settlement control.
This presentation describes the typical rigid inclusion installation technique and the process for design of the system. It describes the geotechnical information required to develop the necessary knowledge of the site conditions and the mechanical properties of the soils required to complete a sustainable design. It focuses on the proper use of cone penetration testing to ascertain the soil conditions at a rigid inclusion site. Key design steps are described in the presentation, with a discussion on numerical modeling of the system and its advantages.
A significant portion of the presentation is dedicated to a discussion of QA/QC methods, including load testing, measurement while drilling (MWD), and expedited methods for interpretation and assessment of MWD data. One or more case histories are used to illustrate all aspects of this presentation, including one where liquefaction potential was mitigated through rigid inclusions.
DOs and DON’Ts IN LATERAL STABILIZATION OF SOILS USING DEEP FOUNDATION ELEMENTS
Besides their main application to support vertical and lateral loading from a superstructrure, deep foundation elements are often subject to lateral loading from the soil itself. In some cases, the foundation elements may need to resist lateral movement of the soil during a potential lateral spreading event in a seismic area, or they may potentially be subject to lateral movement when installed near or below a slope.
This presentation discusses potential situations where deep foundation elements may be required to withstand lateral soil movements. A theoretical, simple slope instability case will be used to illustrate the various steps of analysis, including assessment of movement profile, development of the foundation reaction-displacement function, evaluation of the slope and foundation stability. This example depicts suitable methods of analysis of these systems and will be used to highlight analysis flaws that are often seen in practice.
Several case histories will also be presented that include lateral “squeezing” of soft soils located under or near the edge of an embankment and its effect on driven piles; mitigation of lateral squeeze using drilled foundations; design and testing of augered cast-in-place piles to withstand a lateral spreading event; and slope stabilization using micropiles. Design and construction of these systems, most of which were recently completed, will be discussed in some detail.
|Dan Brown, Ph. D., P.E., D.GE||Chief Engineer and Senior Principal at Dan Brown and Associates.|
|Thomas D. Richards, Jr., P.E., D.GE||Retired chief engineer and current consultant at Nicholson Construction Company|
|David B. Paul, P.E.||Managing partner of Paul GeoTek Engineering and retired from the U.S. Army Corps of Engineers (USACE)|
|Willie M. NeSmith, P.E.||Former chief geotechnical engineer for Berkel & Company Contractors|
|John R. Wolosick, P.E., D.GE, F.ASCE||Director of engineering at Hayward Baker Inc. (HBI) and past president of DFI|