U. S. Department of the Interior Geological Survey
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U. S. DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY USGS SPECTRAL RESPONSE MAPS AND THEIR RELATIONSHIP WITH SEISMIC DESIGN FORCES IN BUILDING CODES OPEN-FILE REPORT 95-596 1995 This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards and stratigraphic nomenclature. Any use of trade, product or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. COVER: The zone type map is based on the 0.3 sec spectral response acceleration with a 10 percent chance of being exceeded in 50 year. Contours are based on Figure B1 in this report. Each zonal increase in darkness indicates a factor two increase in earthquake demand. The lightest shade indicates a demand < 5% g. The next shade is for demand > 10% g. Subsequent shades are for > 20% g, > 40% g, and > 80% g respectively. U. S. DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY USGS SPECTRAL RESPONSE MAPS AND THEIR RELATIONSHIP WITH SEISMIC DESIGN FORCES IN BUILDING CODES by E. V. Leyendecker1 , D. M. Perkins2, S. T. Algermissen3, P. C. Thenhaus4, and S. L. Hanson5 OPEN-FILE REPORT 95-596 1995 This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards and stratigraphic nomenclature. Any use of trade, product or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 1 Research Civil Engineer, U.S. Geological Survey, MS 966, Box 25046, DFC, Denver, CO, 80225 2 Geophysicist, U.S. Geological Survey, MS 966, Box 25046, DFC, Denver, CO, 80225 3 Associate and Senior Consultant, EQE International, 2942 Evergreen Parkway, Suite 302, Evergreen, CO, 80439 (with the U. S. Geological Survey during the time of the spectral response map preparation) 4 Principal Geologist, EQE International, 2942 Evergreen Parkway, Suite 302, Evergreen, CO, 80439 (with the U. S. Geological Survey during the time of the spectral response map preparation) 6 Computer Scientist, U.S. Geological Survey, MS 966, Box 25046, DFC, Denver, CO, 80225 TABLE OF CONTENTS Page List of Figures ............................................................... iii List of Tables ............................................................... vii Abstract ..................................................................... 1 Introduction .................................................................. 2 Use of Maps in Building Codes ................................................... 3 Development and Use of Probabilistic Maps ......................................... 6 Selection of Spectral Response Ordinates .......................................... 11 Spectral Ordinate Maps ........................................................ 13 Development of Design Spectra ................................................. 14 Truncation .................................................................. 15 Truncation Multiplier .......................................................... 15 Conclusions and Future Plans ................................................... 16 Acknowledgments ............................................................ 16 References .................................................................. 17 Appendix A - USGS Peak Ground Motion Maps and Maps in Building Codes and Related Documents ............................................... 20 Appendix B - 1994 Spectral Response Ordinate Maps ............................... 30 Appendix C - 1991 Spectral Response Ordinate Maps ............................... 39 Appendix D - Use of Probabilistic Ground Motion Maps in Building Codes and Related Documents ............................................... 48 Appendix E - Basis of Maps .................................................... 53 n Ill LIST OF FIGURES Figure 1. Variation of the lateral force coefficient with the building period in the 1985 UBC. ........................................................ 4 Figure 2. Variation of the lateral force coefficient with the building period in the 1985 NEHRP Provisions. ............................................ 5 Figure 3. Variation of the lateral force coefficient with the building period in the 1988 UBC. ........................................................ 6 Figure 4. Location of twelve cities used to study spectral shapes .................... 11 Figure 5. Normalized response spectra for 5 percent damping for an exposure time of 50 years with 10 percent probability of exceedance ..................... 12 Figure 6. Comparison of complete and approximate response spectrum for two cities representative of Groups 1 and 2. SA is in units of a fraction of gravity. ....... 12 Figure 7. Determination of 5 percent damped elastic response spectrum. .............. 13 Figure 8. Comparison of complete and approximate response spectrum for two cities representative of Groups 1 and 2. SA is in units of a fraction of gravity. ....... 14 Figure 9. Proposed design equation. ........................................... 15 Figure 10. Comparison of response spectrum with design curves for San Francisco. SA is in units of a fraction of gravity. .................................. 15 Figure Al. 1976 Contour map for horizontal acceleration (expressed as a percent of gravity) in rock with a 10 percent probability of being exceeded in 50 years. The maximum acceleration within the 60 percent contour along the San Andreas and Garlock faults in California is 80 percent of gravity. After Algermissen and Perkins, 1976. ...................................... 21 Figure A2. Contour map for effective peak acceleration (EPA) coefficient, Aa, for the continental United States. The units of EPA are expressed as a percent of gravity. After NEHRP Provisions, 1995 (This map was redrawn from the original source, if differences occur, the original source should be used). ..... 22 IV Figure A3. Contour map for effective peak velocity-related acceleration (EPV) coefficient, Av, for the continental United States. The units of EPV are expressed as a percent of gravity. After NEHRP Provisions, 1995 (This map was redrawn from the original source, if differences occur, the original source should be used). ............................................. 23 Figure A4. One of the SEAOC Seismology Committee proposals for the 1988 Uniform Building Code zone map. Zones are identified by the numbers 0 to 4. Seismic zone factors are assigned to each zone: Zone 0 = 0, Zone 1 =0.1, Zone = 0.20 (=0.15 for Zone 2 east of the continental divide), Zone 3 = 0.3, and Zone 4 = 0.4. Each zone also has specific structural detailing requirements. After ICBO, 1986 (This map was redrawn from the original source, if differences occur, the original source should be used). ............ 24 Figure A5. 1988 Uniform Building Code zone map. Zones are identified by the numbers from 0 to 4. Seismic zone factors are assigned to each zone: Zone 0 = 0, Zone 1 = 0.075, Zone 2A = 0.15, Zone 2B = 0.20, Zone 3 = 0.3, and Zone 4 = 0.4. Each zone also has specific structural detailing requirements. After UBC, 1988 (This map was redrawn from the original source, if differences occur, the original source should be used). ..................... 25 Figure A6. 1990 Contour map for horizontal acceleration (expressed as a percent of gravity) in rock with a 10 percent probability of being exceeded in 50 years. After Algermissen et al, 1990. ........................................ 26 Figure A7. 1994 Uniform Building Code zone map. Zones are identified by the numbers from 0 to 4. Seismic zone factors are assigned to each zone: Zone 0 = 0, Zone 1 = 0.075, Zone 2A = 0.15, Zone 2B = 0.20, Zone 3 = 0.3, and Zone 4 = 0.4. Each zone also has specific structural detailing requirements. After UBC, 1994 (This map was redrawn from the original source, if differences occur, the original source should be used). ..................... 27 Figure A8. ASCE A7 contour map for effective peak acceleration (EPA) coefficient, Aa, for the continental United States. The units of EPA are expressed as a percent of gravity. After ASCE A-7,1994 (This map was redrawn from the original source, if differences occur, the original source should be used). ...... 28 Figure A9. ASCE A7 contour map for effective peak acceleration (EPV) coefficient, Av, for the continental United States. The units of EPV are expressed as a percent of gravity. After ASCE A-7,1994 (This map was redrawn from the original source, if differences occur, the original source should be used). ...... 29 Figure B1. 1994 contour map of the 5 percent damped 0.3 second pseudo-acceleration spectral response, expressed in percent of the acceleration of gravity, with a 10-percent probability of exceedance in 50 years. The map values include estimates of variability in the attenuation of spectral acceleration and in fault rupture length. ................................................ 31 Figure B2. 1994 contour map of the 5 percent damped 1.0 second pseudo-acceleration spectral response, expressed in percent of the acceleration of gravity, with a 10-percent probability of exceedance in 50 years. The map values include estimates of variability in the attenuation of spectral acceleration and in fault rupture length. ................................................ 32 Figure B3. 1994 contour map of the 5 percent damped 0.3 second pseudo-acceleration spectral response, expressed in percent of the acceleration of gravity, with a 10-percent probability of exceedance in 250 years. The map values include estimates of variability in the attenuation of