19th C. W. Lovell Distinguished Lecture
Wednesday, September 24, 2025 @ 4:30 p.m.
Burton D. Morgan Center for Entrepreneurship, Room 121
Purdue University - West Lafayette, IN
Professor Jonathan P. Stewart
University of California, Los Angeles
Foundation Performance of Millennium Tower in San Francisco, California
The Millennium Tower is a 58-story reinforced concrete building that was constructed in San Francisco, California between 2005 and 2009. The Tower is founded on an embedded pilesupported mat with pile tips bearing in dense marine deposits that overlie an over-consolidated marine clay layer known locally as Old Bay Clay. This clay layer experienced stress increases from Tower self-weight and from multiple episodes of de-watering between 2006 and 2018 at the Tower site and neighboring sites. Settlements of the Tower foundation have been measured since 2006 and lateral deflections of the Tower have been inferred and measured since 2009. Available information on this case history include geotechnical site conditions and data from a monitoring program that tracked foundation settlements, Tower tilt, groundwater levels at the Tower site, and ground inclinations over time. This presentation will present the case history and its significance, discuss the ground deformation mechanisms that caused the observed movements, describe the degree to which the movements can be predicted, and discuss lessons from this case history for the design of deep foundations for tall buildings in San Francisco and geologically similar regions.
About Professor Jonathan P. Stewart
Jonathan P. Stewart’s technical expertise is in geotechnical engineering, earthquake engineering, and seismology. He works on problems related to hazard characterization (ground motion, ground failure) and infrastructure response to those hazards (soil-structure systems, distributed infrastructure systems). He has held leadership positions at UCLA (Department Chair), ASCE (Committee Chair, Journal Editor), EERI (Board of Directors, Journal Editor), and federal and state government panels and committees related to seismic risk. He is an elected member of the US National Academy of Engineering.
