GEOLOGICAL ENGINEERING INPUT TO DESIGN AND CONSTRUCTION OF THE

FOOTHILL STUDENT HOUSING PROJECT, UNIVERSITY OF CALIFORNIA,

BERKELEY, ALAMEDA COUNTY, CALIFORNIA

By William Godwin and Stephen Korbay

ABSTRACTGeological engineering input was essential to the success of a student housing project on the University of California campus in Berkeley, California. Design considerations included (1) identifying zones of active, Holocene faulting and establishing setbacks from these zones, (2) evaluating impacts of earthquake-induced ground shaking on structures, (3) evaluating slope stability and active landsliding, (4) determining subsurface drainage and hydrostatic conditions upslope of the fault zone and (5) predicting differential settlement under foundations.

The site is located in the Berkeley Hills Area of the Coast Ranges geomorphic province of Northern California. A key geologic feature of the site is the northwest-trending Hayward fault, an active segment of the San Andreas fault system. Landslide deposits are found adjacent to the fault and immediately upslope of the planned facilities. Several geotechnical investigations have been performed in the area, and have included logging of fault trenches, excavation of test pits, description and sampling rock and soil borings, the installation of borehole instrumentation, and geologic mapping.

During construction, the geotechnical consultant provided monitoring and testing services. Structures built included nine three-story dormitory residences founded on lateral spread footings, a 25-ft high tieback soldier pile wall built to retain an existing roadway, and gravity-type crib retaining walls to support fills placed for the parking areas. Landslide remediation included construction of an engineered buttress fill and installation of horizontal drains. Post-construction monitoring was performed to evaluate settlement and slope stability.