Long-Period Transition Maps Location of Deterministic Areas

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1 Seismic Ground Motions GROUND MOTION MAPS How To Obtain the Basic Values 1 Determine basic values from maps for bedrock conditions 2, 3 Classify soil conditions at site and determine site coefficients 4 Determine site-adjusted values 4 Take two-thirds for use in design 5 Construct design response spectrum 7 Site-specific studies permitted/required Ground Motion Maps 5b - 1 Ground Motion Maps 5b - 2 Mapped Acceleration Parameters Two sets of maps; acceleration parameter is in units of gravity S S for spectral response acceleration at 0.2 sec S 1 for spectral response acceleration at 1.0 sec Shortcut to Seismic Design Category A: S S < 0.15 and S 1 < 0.04 Ground Motion Parameters & Seismic Hazard Mapped Contours of S S S S and S 1 are the mapped 2% in 50 year spectral accelerations for firm rock S DS and S D1 are the design level spectral accelerations (modified for site and expected good performance ) Ground Motion Maps 5b - 3 Ground Motion Maps 5b - 4 Long-Period Transition Maps Location of Deterministic Areas Ground Motion Maps 5b - 5 Ground Motion Maps 5b - 6 FEMA 451B Topic 5b Handouts Ground Motion Maps 1

2 Typical Probabilistic Map CD vs Internet Internet CD Both sources give the same answers Both sources have a similar user interface The graphics are somewhat different Ground Motion Maps 5b - 7 Ground Motion Maps 5b - 8 Internet Ground Motion Tool USGS Ground Motion Calculator SEISMIC DESIGN VALUES FOR BUILDINGS S s and S 1, Hazard Curves, Uniform Hazard Spectra, and Residential Design Category Ground Motion Maps 5b - 9 Ground Motion Maps 5b - 10 Installation Installation Caution Ground Motion Maps 5b - 11 Ground Motion Maps 5b - 12 FEMA 451B Topic 5b Handouts Ground Motion Maps 2

3 Opening Screen Analysis Options Ground Motion Maps 5b - 13 Ground Motion Maps 5b - 14 IBC Option User Aids Ground Motion Maps 5b - 15 Ground Motion Maps 5b - 16 Calculate S S AND S 1 Location By Zipcode Ground Motion Maps 5b - 17 Ground Motion Maps 5b - 18 FEMA 451B Topic 5b Handouts Ground Motion Maps 3

4 Calculate S MS, S M1, S DS, S D1 Calculate Site Coefficients Ground Motion Maps 5b - 19 Ground Motion Maps 5b - 20 S MS, S M1, S DS, S D1 Values Calculate MCE Spectrum Ground Motion Maps 5b - 21 Ground Motion Maps 5b - 22 Calculate S M Spectrum Calculate S D Spectrum Ground Motion Maps 5b - 23 Ground Motion Maps 5b - 24 FEMA 451B Topic 5b Handouts Ground Motion Maps 4

5 Graphic Options Map Spectrum: S a -T Ground Motion Maps 5b - 25 Ground Motion Maps 5b - 26 All Spectra: S a -T Calculate Hazard Curves Ground Motion Maps 5b - 27 Ground Motion Maps 5b - 28 Annual Frequency of Exceedance Return Period Ground Motion Maps 5b - 29 Ground Motion Maps 5b - 30 FEMA 451B Topic 5b Handouts Ground Motion Maps 5

6 Single Values Deaggregation Breaking apart of the probabilistic hazard analysis Helps remove some of the black box effect Helps visualize the source of the hazard Many uses, e.g. liquefaction analysis, time history determination Ground Motion Maps 5b - 31 Ground Motion Maps 5b - 32 Deaggregation San Francisco Deaggregation - Coos Bay, Oregon Ground Motion Maps 5b - 33 Ground Motion Maps 5b - 34 Deaggregation - Portland, Oregon Deaggregation Olympia, Washington Ground Motion Maps 5b - 35 Ground Motion Maps 5b - 36 FEMA 451B Topic 5b Handouts Ground Motion Maps 6

7 Seattle 0.2 sec, Detailed Seattle 0.2 sec Ground Motion Maps 5b - 37 Ground Motion Maps 5b - 38 Seattle 1.0 sec Design Values Outside the United States Based on GASHAP Data 10% PE in 50 years PGA only Estimate 2% from 10% PE by multiplying by 2.0 S s = 2.5xPGA S 1 = PGA Use site-specific studies where available USGS studies where available Ground Motion Maps 5b - 39 Ground Motion Maps 5b - 40 UFC What is GSHAP? Ground Motion Maps 5b - 41 Ground Motion Maps 5b - 42 FEMA 451B Topic 5b Handouts Ground Motion Maps 7