Time:
03:00 PM - 03:55 PM
Date:
15 September 2020

San Francisco’s Millennium Tower Retrofit

Developed 2005–2009, San Francisco’s 56-story Millennium Tower was designed to be the city’s premier residential address. Homeowners included football great Joe Montana, the Warrior’s Steph Curry, the Giant’s Hunter Pence. Developed at a cost of $600 Million, units sold for a total of $750 Million, with the most expensive unit sold in 2009 for $13.5 million. Although the original geotechnical report predicted from 4 to 6 inches of total settlement, by 2014 the building had settled more than 14 inches. Litigation initiated in 2015 with homeowners alleging the building did not meet code, was unsafe, and required a $300 Million retrofit consisting of installation of more than 400 piles extending though the 10 foot thick foundation mat to rock, located approximately 250 below grade. Ultimately, Simpson Gumpertz & Heger worked with Slate Geotechnical Engineers to demonstrate the building met applicable building code criteria and safety-related performance goals. However, to address homeowner claims of diminished value, the mediation included a voluntary foundation upgrade comprising the installation of 52 piles, extending to rock. The presentation will include an overview of the conditions that resulted in the large building settlement and tilting, the structural and geotechnical analyses performed and the details of the retrofit.

Moderator

  • Ronald O. Hamburger, PE, SE, FSEI, Senior Principal, Simpson Gumpertz & Heger, Inc. San Francisco

Speakers

  • Ronald O. Hamburger, PE, SE, FSEI, Senior Principal, Simpson Gumpertz & Heger, Inc. San Francisco
  • Dr. Nathaniel Wagner, PE, MGEI, Project Engineer, Slate Geotechnical Consultants, Oakland, CA