This document summarizes the geology and construction of excavations for the UC Berkeley Stanley Hall Replacement Project. Key points: - The project involved replacing an existing building with 3 basement levels extending to 75 feet deep in an urban environment near the Hayward Fault. - Geotechnical investigations identified complex subsurface geology including fill, sandstone, shale, mudstone breccia, serpentinite, and the Louderback Shear Zone fault. - Excavation required demolition, dewatering, micropile and conventional foundations, and soil nail shoring walls up to 40 feet high. - Detailed geologic mapping of the excavation faces during construction revealed differences from pre-construction interpretations

1. CONFIRMATION OF SUBSURFACE
GEOLOGIC CONDITIONS OF THE
UC BERKELEY STANLEY HALL
REPLACEMENT PROJECT BY
CONSTRUCTION FIELD
OBSERVATIONS
Presented by:
William Godwin CEG, Ryan Shafer PE, and Chris Muller GE
MACTEC Engineering & Consulting, Inc.
Annual Meeting
The Geological Society of America
Seattle, Washington
November 2, 2003

2. Introduction
Purpose of Paper:
Discuss the importance of geologic
mapping of large excavations that
expose heterogenous materials
Present engineering geologic
conditions of the project

3. Topics
 Project Description
 Challenges
 Geotechnical Investigation
 Geologic Conditions
 Construction Methodology
 Geologic Mapping
 Conclusions

4. Project Description
Bay Area Hazard Zones
http://gmw.consrv.ca.gov/shmp

5. Site
Project Description
U.C. Berkeley Campus
N

6. Key Elements
Replacement of existing
classroom building
Accommodate 3 basement
levels to -75 feet
Seismic design to
withstand Mmax 7.1 on
Hayward Fault 500 feet
away
Project Description

7. Team
 UCB Capital Projects – Owner/Builder
 Zimmer Gunsul Frasca Partnership –
Architect
 BKF Engineers/Surveyors/Planners –
Civil Engineer
 MACTEC E&C – Geotechnical Engineer
 Rutherford & Chekene – Structural Engineer
 Pirooz Baraar Associates – Retention
Systems Engineer
 McCarthy – General Contractor
Project Description

8. Challenges
 Urban environment
 Adjacent structures
 Complex ground conditions
and geology

9. Geotechnical Investigation
Exploration Plan

10. Geotechnical Investigation
Program
 Previous Investigations
 Deep coreholes
 Laboratory testing
 Geophysical surface surveys

11. Recommendations
 Stability
 Excavatability
 Dewatering
 Shoring design criteria
Geotechnical Investigation

12. Geologic Conditions
Local Fault Map

13. Geologic Conditions
Geologic Units and Structure
 Fill and Alluvium
 Greywacke Sandstone
 Shale and Mudstone Breccia
 Serpentinite and Melange
 Louderback Shear Zone

14. Construction Methodology
 Demolition and excavation
 Dewatering
 Foundations
 Shoring

15. Construction Methodology
Demolition Excavation

16. Construction Methodology
Dewatering
and Seepage
Control

17. Construction Methodology
Foundations
 Micropiles
 Conventional
Footings and
Structural Mat

18. Construction Methodology
South Wall Shoring Plan

19. Construction Methodology
Shoring Plan: Soil Nails

20. Geologic Mapping
 Digital photography
 Sequential face mapping
 Seepage and overbreak
 Geologic contacts

21. Geologic Mapping
T
P
390.00
380.00
370.00
360.00
350.00
340.00
330.00
320.00
310.00
300.00
T
T
T
T
T
T
P
T
T
T
T
T T
T
T
T
T
T
T
ELEVATION
IN FEET
SOUTH WALL ELEVATION

22. Geologic Mapping

23. Geologic Mapping

24. Geologic Mapping
East Wall Mudstone
Breccia/Melange
West Wall Interbedded
Sandstone/Shale

25. Geologic Mapping
?
?
?
?
? ?
S O U T H W AL L
DONNER LAB
GRAYWACKE
SANDSTONE
BRECCIATED
MUDSTONE
AND SHALE
INTERBEDDED
SANDSTONE AND SHALE
CARBONACEOUS
SHEARED AND
SERPENTINITE
SHALE WITH
Site Geology

26. Conclusions
 Conditions: Interpreted vs. Actual
– Bedrock contacts
– Excavatability
– Stability
– Groundwater
– Bonding strength
– Wall movement

27. Conclusions
Identify potential unstable zones
that could impact shoring system or
worker safety
Presence of Louderback Shear zone
and understanding of local geology
Integration of observational and
construction methodology and
applicability to future projects