Invited Speaker: A History of Deep Foundations in San Francisco-PPT Presentation

PPT Presentation

Pdf Summary

The presentation traces the development of deep foundations in San Francisco from early settlement through modern construction. The city’s geology includes challenging subsurface conditions, while nearby faults and earthquake-related liquefaction and landslide hazards have strongly influenced foundation design.<br /><br />During the Gold Rush (1848–1855), rapid growth led to construction on waterfront fill and soft ground. An 1850 attempt to drive bridge piles reportedly sent piles more than 80 feet into the ground without reaching firm support, and the project was abandoned. Buried ships in Yerba Buena Cove illustrate how the shoreline was extended and developed.<br /><br />The 1906 earthquake and fire devastated much of the city, prompting extensive rebuilding. Development of the Marina District followed the 1915 Panama-Pacific International Exposition. Foundation methods evolved over time: timber piles were used from the 1800s onward; early concrete piles, drilled shafts, belled piers, and steel piles followed; and precast prestressed concrete piles became common from the 1950s. More recent options include helical piers, micropiles, augered cast-in-place and drilled displacement piles, and other specialized systems.<br /><br />The presentation also considers the effects of the 1989 Loma Prieta earthquake and examines two areas in detail. Mission Bay, developed largely from 2000 onward on former shoreline and fill, uses a range of pile and shaft systems. In the Transbay neighborhood, deep foundations must penetrate complex mélange and Franciscan bedrock; rock-socketed drilled shafts support newer high-rise construction. Overall, San Francisco’s foundation history reflects the need to adapt engineering methods to changing technology, urban growth, difficult ground, and seismic risk.

Keywords

San Francisco

deep foundations

geology

earthquake hazards

liquefaction

foundation design

Gold Rush

timber piles

drilled shafts

Mission Bay