Seismic Issues and Building Codes for Kentucky

Transcription

1 Seismic Issues and Building Codes for Kentucky Zhenming Wang, PhD, PE Kentucky Geological Survey University of Kentucky KSPE Annual Convention April 28, 2011

2 Outline Introduction Design Ground Motion Maps for Building Codes The USGS Seismic Hazard Maps The KGS Seismic Hazard Maps Summary

3 2010 Haiti Earthquake (M7.1)

4 (Modern building) (Adobe) (Reinforced Concrete) 2010 Chile Earthquake (M8.8)

5 (Reinforced Concrete) 2011 Japan Earthquake (M9.0)

6 2011 Japan Earthquake (M9.0) (Reinforced Concrete) Earthquake (ground shaking) damages are not severe in Sendai.

7 Nuclear Disaster

8 It was tsunami caused the backup generator failure lost cooling Design PGA on base-rock: 0.6g ( for all) Design PGA at No.5 base-mat: 0.45g Observed PGA at the base-mat: No. 3: 0.51g No. 4: 0.32g No. 6: 0.43g (Irikura, 2011) (Masaki and Koike, 2011)

9 The best way to prevent earthquake disaster is to build better seismic resistant infrastructure, buildings, and others The seismic provisions in building codes are important

10 Seismic Codes and Source Documents - Past NEHRP Provisions ASCE 7 (Seismic) SEAOC Blue Book Standard Building Code BOCA National Building Code Uniform Building Code International Building Code (Kircher, 2010)

11 Seismic Codes and Source Documents Current NEHRP Provisions ASCE 7 (Seismic) International Building Code NFPA 5000 Building Code California Building Code (Kircher, 2010)

12 Development of NEHRP Design Ground Motion Science Seismic Hazard Map (USGS) BSSC Seismic Design Procedures Reassessment Group (SDPRG) Policy Seismic Design Ground Motions (FEMA) Federal agencies State Agencies Other organizations

13 Seismic Design Procedures Reassessment Group Project 07 Joint effort of the BSSC, FEMA and USGS Scope/Objectives Revisit products of Project 97 in light of new seismic hazard information (developed by the USGS) Develop revised seismic design maps and procedures reflecting these new data for inclusion in the 2009 NEHRP Procedures (and ASCE/SEI 7-10 and model building codes) Members Dr. Charles A. Kircher, PE (SDPRG Chair) Dr. C. B. Crouse, PE (PUC TS-3 Chair) Prof. Bruce R. Ellingwood, PE, Georgia Tech Mr. Ronald O. Hamburger, SE (PUC Chair) Prof. Robert D. Hanson, FEMA (tech. advisor) Dr. James R. Harris, SE (ASCE 7 past Chair) Dr. John Jack R. Hayes, PE, NIST (NEHRP) Mr. William T. Holmes, SE (PUC past Chair) Mr. John D. Hooper, SE (ASCE 7 SSC Chair) Dr. Jeffrey K. Kimball, DOE NNSA Dr. Nicolas Luco, USGS Prof. Andrew Whittaker, SE, SUNY Buffalo Mr. Michael Mahoney, FEMA (Kircher, 2010)

14 NEHRP Design Map 0.2 sec Spectral Response Acceleration for the U.S. (2% PE in 50 yrs., NEHRP) 2 g 4 g (2009 NEHRP Provisions)

15 California Two times gravity Central U.S. San Francisco Paducah Memphis Four times gravity NEHRP 0.2 sec Spectral Response Acceleration

16 NEHRP Design Map 1.0 sec Spectral Response Acceleration for the U.S. (2% PE in 50 yrs., NEHRP) 1 g 2 g (2009 NEHRP Provisions)

17 California Central U.S. One times gravity Paducah San Francisco Memphis Two times gravity 1.0 sec Spectral Response Acceleration

18 Problems in western Kentucky 1) In 2001, Mr. David Master (a staff member from KY congressman Ed Whitfield office): Why can I not build a regular two-story house in Paducah? 2) SEAOK found that: impossible to construct residential structures in westernmost Kentucky without enlisting a design professional (IRC-2000). 3) DOE will not get permit from Ky-EPA to build a landfill at PGDP for clear-up. 4) In 2002, One of the main reasons that Kentucky lost the centrifuge facility ($2B) to Ohio.

19 Closing Comments (Code Perspective) Code Ground Motions New risk-targeted ground motions of ASCE 7-10 (and the 2009 NEHRP Provisions) are now approved for use in model building codes (e.g., 2012 IBC) almost, but not yet law Code Development Process (NEHRP) BSSC NIBS (FEMA) Developed collapse risk concepts for new ground motions ATC-63 (FEMA P-695) Provided methods and established the basis for generic building collapse risk safety goals USGS Developed risk-targeted ground motions based on the above and best available (current) science (Kircher, 2010)

20 USGS 7-Day Seismicity in the U.S.

21 USGS Twenty-Year Did You feel It U.S. G.S. (Leith and others, 2009)

22 California GPS results Central U.S. Deformation rate: > 30 mm/y Deformation rate: < 3 mm/y

23 Active Plate Tectonics Deformation rate: > 30 mm/y Intra-Plate tectonics Deformation rate: < 3 mm/y

24 National Seismic Hazard map for Central U.S. - PGA with 2% PE in 50 years China - Wenchuan earthquake Actual (M7.9) PGA map <0.10g (Wang, 2009) (Peterson and others, 2008) Red area: g

25 0.2 sec Spectral Acceleration, %g 10% in 50 Years 5% in 50 Years 2% in 50 Years Inputs The National Seismic Hazard Maps Modeling (computer) Outputs Scientific data PSHA Hazard curves 10.0 HAZARD CURVES FOR SELECTED CITIES CITIES Los Angeles San Francisco Seattle Salt Lake City New York City Charleston Memphis Annual Frequency of Exceedance (Frankel et al., 1996)

26 0.2 sec Spectral Acceleration, %g 10% in 50 Years 5% in 50 Years 2% in 50 Years PSHA End Results: Seismic Hazard Curves 10.0 HAZARD CURVES FOR SELECTED CITIES (Frankel et al., 1996) CITIES Los Angeles San Francisco Seattle Salt Lake City New York City Charleston Memphis Hazard Hazard curves curves Annual Frequency of Exceedance Hazard maps

27 Ann. frequency of exc.(1/year) Probabilistic Seismic Hazard Analysis PSHA Input A single EQ Sensitivity Test PSHA Computer model Output Infinite GM Source (M7.7 occurrence) Site (GM occurrence) Dis. =30km T RP =? 1.E-02 1.E-03 1.E-04 1.E-05 1.E-06 1.E-07 PGA hazard curve Return period (years) T RI =500 years 1.E E PGA (g) Annual Frequency of Exceedance (fy): The frequency (the number of events per year) that a ground motion is equal to or greater than a specific value

28 Probabilistic Seismic Hazard Analysis PSHA VSAP T RP =500 1,000 years New Madrid Seismic Zone T RI =500-1,000 years

29 PSHA is a mathematical formulation derived from a rigorous probability analysis on distributions of earthquake magnitudes, locations, and ground motion attenuation (McGuire, 2008). t=1 year was omitted!!! (v is the average event [earthquake] occurrence rate [per year]) PSHA calculates: The annual probability of exceedance probability of exceedance in ONE year a dimensionless quantity

30 Probabilistic Seismic Hazard Analysis PSHA (Cornell, 1968) (Cornell, 1968)

31 Return period (years) Yucca Mountain, NV ( 2001 others, (Stepp and 10,000 years 1,000,000 years 11g 100,000,000 years Hanks (2011) concluded that it (11g PGA) is overstated and had no answer what is wrong

32 Development of NEHRP Design Ground Motion Seismic Hazard Map (USGS) Science?????? BSSC engineers, seismologists, and others Seismic Design Ground Motions (FEMA) Policy??????

33 The KGS Scenario/Deterministic Ground Motion Hazard Maps (Wang, 2010)

34 The KGS Scenario/Deterministic Ground Motion Hazard Maps (Wang, 2010)

35 The KGS Scenario/Deterministic Ground Motion Hazard Maps (Wang, 2010)

36 The KGS Scenario/Deterministic Ground Motion Hazard Maps (Wang, 2010)

37 Acceleration (cm/s/s) The KGS Scenario/Deterministic Ground Motion Hazard Maps Horizontal Horizontal-2 KTC-07-06/SPR F (Wang and others, 2007) Vertical Time (sec)

38 Acceleration (cm/s/s) The KGS Scenario/Deterministic Ground Motion Hazard Maps Horizontal Horizontal-2 KTC-07-06/SPR F (Wang and others, 2007) Vertical Time (sec)

39 Problems in western Kentucky 1) In 2001, Mr. David Master (a staff member from KY congressman Ed Whitfield office): Why can I not build a regular two-story house in Paducah? 2) SEAOK found that: impossible to construct residential structures in westernmost Kentucky without enlisting a design professional (IRC-2000). - Revised (similar to the KGS maps) 3) DOE will not get permit from Ky-EPA to build a landfill at PGDP for clear-up. - DOE has submitted a report on scenario/deterministic assessment 4) In 2002, One of the main reasons that Kentucky lost the centrifuge facility ($2B) to Ohio.

40 Summary There is no question that Kentucky does have seismic hazards, but the hazards are not as high as those in California The best way to prevent earthquake disaster is to build better seismic resistant infrastructure, buildings, and others. Thus, the seismic provisions in the building codes are important.

41 Summary The issues and problems related to seismic provisions in the building codes are caused by the national seismic hazard maps The methodology used to produce the maps is not science The scenario/deterministic seismic hazard maps provide good alternatives for engineering design and other considerations

42 Thank You!