2013 Update to the Site-Specific Seismic Hazard Analyses and Development of Seismic Design Ground Motions
Total Page:16
File Type:pdf, Size:1020Kb
FINAL REPORT 2013 UPDATE TO THE SITE-SPECIFIC SEISMIC HAZARD ANALYSES AND DEVELOPMENT OF SEISMIC DESIGN GROUND MOTIONS STANFORD UNIVERSITY, CALIFORNIA Prepared for Stanford University Stanford, California 28 April 2014 Patricia Thomas, Ivan Wong, and Judith Zachariasen URS Corporation Seismic Hazards Group 1333 Broadway, Suite 800 Oakland, California 94612 Robert Darragh and Walt Silva Pacific Engineering & Analysis 856 Seaview Dr. El Cerrito, CA 94530 TABLE OF CONTENTS Executive Summary ............................................................................................................................... ES-1 Section 1 ONE Introduction ..................................................................................................................... 1-1 1.1 Scope of Work .......................................................................................... 1-1 1.2 Acknowledgments.................................................................................... 1-2 Section 2 TWO Seismic Hazard Analyses Methodologies .................................................................... 2-1 2.1 Probabilistic Seismic Hazard Analysis .................................................... 2-1 2.2 Seismic Source Characterization ............................................................. 2-2 2.2.1 Source Geometry ......................................................................... 2-2 2.2.2 Fault Recurrence .......................................................................... 2-3 2.3 Ground Motion Characterization ............................................................. 2-4 2.4 Deterministic Seismic Hazard Analysis ................................................... 2-4 Section 3 THREE Campus Geotechnical Characterization ....................................................................... 3-1 Section 4 FOUR Inputs to Analyses .......................................................................................................... 4-1 4.1 Seismic Sources ....................................................................................... 4-1 4.1.1 Faults ............................................................................................ 4-1 4.1.2 Background Seismicity ................................................................ 4-7 4.2 Ground Motion Prediction Models .......................................................... 4-7 Section 5 FIVE PSHA Results .................................................................................................................. 5-1 Section 6 SIX DSHA Results ................................................................................................................. 6-1 Section 7 SEVEN Site Response Analysis ................................................................................................. 7-1 Section 8 EIGHT Design Response Spectra for New Buildings .............................................................. 8-1 8.1 ASCE 7-10 Methodology ........................................................................ 8-1 8.2 MCER and DRSR for Zones 1, 2 and 3 ..................................................... 8-1 8.3 MCER and DRSR for Zone 0 .................................................................... 8-2 8.4 Design Acceleration Parameters .............................................................. 8-3 Section 9 NINE Design Response Spectra for Existing Buildings........................................................ 9-1 9.1 ASCE 41-13 Methodology ...................................................................... 9-1 9.2 BSE-1E and BSE-2E for Zones 1, 2, and 3 ............................................. 9-1 9.3 BSE-1E and BSE-2E for Zone 0 .............................................................. 9-2 Section 10 TEN Comparison With 2010 Spectra and General Code Spectra ..................................... 10-1 10.1 Comparison of Site-Specific and General Code Design Spectra ........... 10-1 10.1.1 Design Spectra for New Buildings ............................................ 10-1 W:\X_WCFS\PROJECTS\STANFORD UNIV\2013 UPDATE GM\STANFORD PSHA 2013 UPDATE_FINAL.DOCX\28-APR-14\\OAK i TABLE OF CONTENTS 10.1.2 Design Spectra for Existing Buildings ....................................... 10-1 10.2 Comparison With 2010 Spectra ............................................................. 10-2 10.2.1 Design Spectra for New Buildings ............................................ 10-2 10.2.2 Design Spectra for Existing Buildings ....................................... 10-2 Section 11 ELEVEN Conditional Mean Spectra ............................................................................................ 11-1 11.1 CMS Implementation ............................................................................. 11-1 11.2 Example CMS at Stanford ..................................................................... 11-2 Section 12 TWELVE Final Remarks ............................................................................................................... 12-1 Section 13 THIRTEEN References ......................................................................................................................... 1 Appendix A-1 Bay Area Time-Independent Seismic Source Parameters Tables 3-1 VS30 and NEHRP Site Classes 8-1 MCER (BSE-2N) and DRSR (BSE-1N) Spectra 8-2 Design Acceleration Parameters 9-1 BSE-1E and BSE-2E Spectra 10-1 Factors Impacting 84th Percentile Deterministic for Zone 0 Figures 1-1 Historical Seismicity in the San Francisco Bay Region (M 3.0) 1800-2013 1-2 Active Faults in the San Francisco Bay Region 1-3 Active Faults in the Vicinity of the Site 2-1 Seismic Hazard Model Logic Tree 3-1 SASW Survey Locations and Quaternary Geology 3-2 All SASW VS Profiles 3-3 West Campus SASW VS Profiles 3-4 North-Central Campus SASW VS Profiles 3-5 East Campus SASW VS Profiles 3-6 Comparison of Lognormal Average VS Profiles for East and North Central Campus 3-7 West Campus VS Profiles 5-1 Locations of Hazard Computations 5-2 Seismic Hazard Curves for Peak Horizontal Acceleration for Site 1 and Reference Site Condition W:\X_WCFS\PROJECTS\STANFORD UNIV\2013 UPDATE GM\STANFORD PSHA 2013 UPDATE_FINAL.DOCX\28-APR-14\\OAK ii TABLE OF CONTENTS 5-3 Seismic Hazard Curves for 1.0 sec Horizontal Spectral Acceleration for Site 1 and Reference Site Condition 5-4 Comparison of Peak Horizontal Acceleration Hazard for all Sites at Reference Site Condition 5-5 Comparison of 1.0 sec Horizontal Spectral Acceleration Hazard for all Sites at Reference Site Condition 5-6 Seismic Source Contributions to Peak Horizontal Acceleration Hazard for Site 1 and Reference Site Condition 5-7 Seismic Source Contributions to 1.0 Sec Horizontal Spectral Acceleration Hazard for Site 1 and Reference Site Condition 5-8 Magnitude and Distance Contributions to the Mean Peak Horizontal Acceleration Hazard at 225-Year Return Period for Site 1 5-9 Magnitude and Distance Contributions to the Mean Peak Horizontal Acceleration Hazard at 975-Year Return Period for Site 1 5-10 Magnitude and Distance Contributions to the Mean Peak Horizontal Acceleration Hazard at 2,475-Year Return Period for Site 1 5-11 Magnitude and Distance Contributions to the Mean 1.0 Sec Horizontal Spectral Acceleration Hazard at 225-Year Return Period for Site 1 5-12 Magnitude and Distance Contributions to the Mean 1.0 Sec Horizontal Spectral Acceleration Hazard at 975-Year Return Period for Site 1 5-13 Magnitude and Distance Contributions to the Mean 1.0 Sec Horizontal Spectral Acceleration Hazard at 2,475-Year Return Period for Site 1 5-14 Sensitivity of the Peak Horizontal Acceleration Hazard to the Selection of Ground Motion Models for Site 1 and Reference Site Condition 5-15 Sensitivity of the 1.0 Sec Horizontal Spectral Acceleration Hazard to the Selection of Ground Motion Models for Site 1 and Reference Site Condition 5-16 5%-Damped Uniform Hazard Spectra at Reference Site Condition 6-1 Sensitivity of 84th Percentile Horizontal Acceleration Response Spectrum for the M 8.0 San Andreas Maximum Earthquake at 5.5 km to Ground Motion Models 6-2 Sensitivity of 84th Percentile Horizontal Acceleration Response Spectrum for the M 8.0 San Andreas Maximum Earthquake at 7.5 km to Ground Motion Models 6-3 84th Percentile Horizontal Acceleration Response Spectrum for the M 8.0 San Andreas Maximum Earthquake 6-4 Comparison of 84th Percentile Deterministic Spectra Using NGA-West1 and NGA- West2 Ground Motion Models 7-1 Example Randomized Velocity Profiles for North-Central/East Campus for One Bedrock Depth 7-2 Site-Specific Amplification Factors for Ground Motion Level of 0.5 g (PGA) 7-3 5%-Damped Uniform Hazard Spectra for Sites 1, 2, and 3 at the Ground Surface W:\X_WCFS\PROJECTS\STANFORD UNIV\2013 UPDATE GM\STANFORD PSHA 2013 UPDATE_FINAL.DOCX\28-APR-14\\OAK iii TABLE OF CONTENTS 7-4 84th Percentile Horizontal Acceleration Response Spectrum for the M 8.0 San Andreas Maximum Earthquake at the Ground Surface 7-5 Comparison of Uniform Hazard Spectra and 84th Percentile Deterministic Spectra for Sites 1, 2, and 3 at the Ground Surface 7-6 5%-Damped Uniform Hazard Spectra at 225-Year Return Period for Site 0 7-7 5%-Damped Uniform Hazard Spectra at 975-Year Return Period for Site 0 7-8 5%-Damped Uniform Hazard Spectra at 2,475-Year Return Period for Site 0 7-9 84th Percentile Horizontal Acceleration Response Spectrum for the M 8.0 San Andreas Maximum Earthquake at 5.5 km for West Campus 7-10 Comparison of 84th Percentile Deterministic Response Spectra to the 2,475-Year Return Period UHS for