Jonathan D. Bray
453 Davis Hall
On Sabbatical Leave in Fall 2023
Jonathan Bray is a Faculty Chair in Earthquake Engineering Excellence and a Distinguished Professor of Civil and Environmental Engineering at UC Berkeley. Bray’s research focuses on the seismic performance of earth structures, seismic site response, liquefaction, and ground failure and its effects on structures, earthquake fault rupture propagation, and post-event reconnaissance. He was elected into the U.S. National Academy of Engineering and is an ASCE Fellow, among other honors, including the Seed Medal, Terzaghi Award, Ishihara Lecture, Peck Award, Joyner Lecture, Prakash Award, Huber Research Prize, Packard Foundation Fellowship, and the NSF Presidential Young Investigator Award. Bray has authored more than 450 research publications and has served as a consultant on several important engineering projects and peer review panels.
Ph.D., Geotechnical Engineering, University of California, Berkeley, 1990
M.S., Structural Engineering, Stanford University, 1981
B.S., United States Military Academy, 1980
Bray's research focuses on geotechnical engineering and earthquake engineering. His research advances the understanding of earthquake fault rupture effects on systems, ground motions and seismic site effects, liquefaction and its effects on structures, seismic slope stability, and the performance of dams. Much of this research was in response to issues raised following significant earthquakes. Bray has supervised the research of over 30 Ph.D. students. Some of his contributions include:
- Bray and Sancio (2006) liquefaction of fine-grained soil criteria - These criteria followed observations of silt liquefaction in the 1999 Kocaeli, Turkey earthquake (Bray et al. 2004). Field evidence of liquefaction and its effects on buildings in Adapazari, Turkey, and laboratory testing performed on Adapazari silt of different plasticity indices demonstrated soil mineralogy governed its response, not soil particle size.
- Bray and Macedo (2019) seismic slope displacement procedure - The simplified seismic slope displacement procedures of Bray and Travasarou (2007, 2009) were updated by increasing the number of ground motions by a factor of nearly ten and enhancing the sliding block model to create the Bray and Macedo (2019) procedure. Additionally, the unique characteristics of interface earthquakes in subduction zones were captured with the Bray et al. (2018) procedure. The models in these procedures are calibrated to provide results consistent with post-earthquake field measurements of natural earth slopes, earth dams, and municipal solid waste (MSW) landfills.
- Geotechnical Extreme Events Reconnaissance (GEER) - Bray created the NSF-sponsored GEER Association to capture perishable post-earthquake data. Damages observed during earthquakes have motivated several of Bray’s studies. Geotechnical mitigation measures proposed by Oettle and Bray (2013) are well-founded by observations of the effects of surface fault rupture following several earthquakes. The devastating effects of near-fault, pulse ground motions due to forward-directivity led to characterization schemes developed by Bray et al. (2009) and Hayden et al. (2014). The seismic performance of MSW landfills and the engineering properties of MSW with insights on its shear strength by Bray et al. (2009) resulted from observations of the seismic performance of MSW landfills following the 1994 Northridge earthquake.
- Effects of soil liquefaction on buildings - Recent studies documenting and discerning lessons from the impact of liquefaction on buildings in Christchurch, New Zealand (e.g., Bray et al. 2014, 2017) have provided critical insights on the essential roles of the CPT and cyclic laboratory testing to characterize soil deposits and on the use of dynamic soil-structure-interaction (SSI) analysis to evaluate shear-induced liquefaction building settlement. A simplified procedure for assessing liquefaction-induced building settlement is proposed in his 2017 Ishihara Lecture. He recently added a procedure to estimate liquefaction-induced ground settlement in his 2022 Seed Medal Lecture.
RESEARCH PROJECTS:
"Assessment of the Performance of the Ground and Facilities at Wellington Port during Three Earthquakes,” National Science Foundation, 04/20-03/23, $480,382; Principal Investigator.
“Performance Based Earthquake Engineering Assessment Tool for Gas Storage and Transmission System,” California Energy Commission, 12/19-03/22, $4,940,158; Principal Investigator.
“Detailed Evaluation of Insightful Liquefaction Ejecta Case Histories,” U.S. Geological Survey, National Earthquake Hazards Reduction Program, 06/20-05/21, $96,974; Principal Investigator.
“Liquefaction-Induced Ground Settlement Procedure,” State of California, Department of Transportation (Caltrans), 10/21-9/22, $65,000; Principal Investigator.
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CPT CASE HISTORIES OF POST-LIQUEFACTION FREE-FIELD GROUND SETTLEMENT
Franklin Olaya and Professor Jonathan D. Bray developed a CPT-based post-liquefaction free-field ground settlement case history database described in the report provided below with the flatfile which is also provided below (other appendices are available through links below and in the report):
Case Histories Summary Flatfile - Appendix A
Case Histories - Appendices C - I
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Detailed Evaluation of Insightful Liquefaction Ejecta Case Histories for the Canterbury Earthquake Sequence, New Zealand
Zorana Mijic and Professor Jonathan D. Bray in collaboration with Dr. Sjoerd van Ballegooy developed an liquefaction ejecta database described in the report provided below with two electronic appendices which are also provide below:
Detailed Ejecta Case Histories - Appendix A (large PDF file that documents each case history)
Detailed Ejecta Case Histories Summary Flatfile - Appendix B
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Simplified Procedure for Estimating Liquefaction-Induced Building Settlement
Professor Jonathan D. Bray in collaboration with Dr. Jorge Macedo developed a simplified procedure for estimating liquefaction-induced building settlement. The procedure is described in this paper:
Bray, J.D. and Macedo, J. (2017) “6th Ishihara Lecture: Simplified Procedure for Estimating Liquefaction-Induced Building Settlement,” Soil Dynamics and Earthquake Engineering J., V 102, 215-231, https://doi.org/10.1016/j.soildyn.2017.08.026.
This procedure includes a method for estimating Shear-Induced Liquefaction Building Settlement. It is implemented in the program CLiq v.2.0 (https://geologismiki.gr/products/cliq/). A spreadsheet for performing this calculation is also provided below:
Bray & Macedo (2017) Shear-Induced Liquefaction Building Settlement
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Simplified Seismic Slope Displacement Procedures
Professor Jonathan D. Bray in collaboration with Dr. Jorge Macedo and Dr. Thaleia Travasarou developed simplified procedures for evaluating the seismic slope stability of earth/waste structure and natural slopes. The procedures are described in these papers:
Bray, J.D. and Travasarou, T. (2007) “Simplified Procedure for Estimating Earthquake-Induced Deviatoric Slope Displacements,” J. of Geotech. & Geoenv. Engrg., ASCE, Vol. 133(4), 381-392.
Bray, J.D. and Travasarou, T. (2009) “Pseudostatic Coefficient for Use in Simplified Seismic Slope Stability Evaluation,” J. of Geotechnical and Geoenv. Engineering, ASCE, 135(9), 1336-1340.
Bray, J.D., Macedo, J., and Travasarou, T. (2018) “Simplified Procedure for Estimating Seismic Slope Displacements for Subduction Zone Earthquakes,” J. of Geotechnical and Geoenvironmental Engineering, ASCE, V. 144(3): 04017124, DOI: 10.1061/(ASCE)GT.1943-5606.0001833.
Bray, J.D., and Macedo, J. (2019) “Procedure for Estimating Shear-Induced Seismic Slope Displacement for Shallow Crustal Earthquakes,” J. of Geotechnical and Geoenvironmental Engineering, ASCE, V. 145(12), doi: 10.1061/(ASCE)GT.1943-5606.0002143.
Bray, J.D., and Macedo, J. (2023) “Performance-Based Seismic Assessment of Slope Systems,” Soil Dynamics and Earthquake Engineering J., V. 168, 10.1016/j.soildyn.2023.107835.
Macedo, J., Bray, J.D., and Liu, C. (2023) “Seismic Slope Displacement Procedure for Interface and Intraslab Subduction Zone Earthquakes,” J Geotech Geoenviron Eng., ASCE, in press.
The most recent procedures (e.g., Bray and Macedo 2019, and Macedo et al. 2023) are provided in this Simplified Seismic Slope Stability Excel Spreadsheet:
B&M19_MBL23-Seismic-Slope-Displacement
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Oso Landslide State of Washington Reports
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Liquefaction Sediment Ejecta Estimates
The Ejecta Potential Index (EPI) captures key aspects of the hydraulic processes of liquefaction manifestation. Its use is described in Hutabarat, D., and Bray J.D. (2021) “Seismic Response Characteristics of Liquefiable Sites with and without Sediment Ejecta Manifestation,” J. of Geotechnical and Geoenvironmental Engineering, ASCE, 10.1061/(ASCE)GT.1943-5606.0002506, in press.
Supporting files for the Hutabarat & Bray (2021) paper are provided below:
Animations (uploaded at ASCE JGGE site with paper)
Sensitivity Results - Layer Stratification
Sensitivity Results - Ground Motion
Sensitivity Results - Groundwater Level
Sensitivity Results - Hydraulic Conductivity
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Modified-UBCSAND User-Defined Model
This model was developed at UC Berkeley by Dr. Nicolas K. Oettle in collaboration with Professor Jonathan D. Bray. The models are based on UBCSAND developed by Professor Peter Byrnes, Michael Beaty, et al. Documentation of UBCSAND can be found on the FLAC website. The modifications to the UBCSAND model for use in surface fault rupture interaction analysis can be found in these papers:
Oettle, N, and Bray, J.D., “Fault Rupture Propagation through Previously Ruptured Soil,” JGGE, ASCE, Vol. 139(10), 2013, pp. 1637-1647.
Oettle, N, and Bray, J.D., “Geotechnical Mitigation Strategies for Earthquake Surface Fault Rupture,” JGGE, ASCE, Vol. 139(11), 2013, pp. 1864-1874.
Modified-UBCSAND Model:
FLAC6 DLL for modUBCSAND
FLAC7 DLL for modUBCSAND
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