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WEIDLINGER ASSOCIATES©INC • 375 HUDSON STREET, NEW YORK, NY 10014 • PHONE 212 367.3000 • FAX 212 367.3030 • WAI.COM
PROJECT NAME: Olmsted PROJECT LOCATION: FLUSHING, NEW YORK
REPORT NAME: Site Specific Design Spectrum
DATE OF ISSUE: OCTOBER 23, 2009
PREPARED FOR: BKSK Architects LLP
28 W. 25th Street
New York, New York 10010
Contents
1 Purpose of Analysis 1
2 Soil Profiles 1
3 Rock Motions 2
4 Site Specific Design Spectrum 2
5 Reference 9
i
2 SOIL PROFILES 1
1 Purpose of Analysis
Calculate the site specific design spectra for Olmsted Center, Corona Park Queens (Flushing), New
York, using ProShake. The spectra are in horizontal and vertical directions and calculated for three
different earthquakes: (1) 500 year return period earthquake (for service limit); (2) 1500 year return
period earthquake; (3) 2500 year return period earthquake (for strength limit).
2 Soil Profiles
Based on the technical report ”Shear Wave Velocity Survey, The Olmsted Center, Corona Park
Queens (Flushing), New York” by Hager-Richter Geoscience, Inc. (Reference 1), there are four soil
layers to the depth of 100 feet. This report doesn’t provide the soil information below the depth of
100 feet.
The soil layers between the depth of 100 feet to 250 feet is obtained from the technical report
”Subsurface Investigation and Analysis, Proposed Olmsted Center Building Addition, Olmsted
Center, Queens (Flushing), New York” by Richard S. Kessler (Reference 2).
From reference 2, the bedrock is more than 300 feet below existing site grades. The soil layers
between 250 feet depth to the bedrock are assumed based on our past experience.
All the soil layer information is summarized in the following table:
Table 1: Soil layers used to perform site specific analysis
Soil LayerThickness Depth Density Vs G
(ft) (ft) (pcf) (fps) (ksf)
Fill and Peat 14 14 101 364 416Organic Silt 5 19 85 205 111Organic and Inorganic Silt and Clay 34 53 104 340 374Silty Sand 47 100 115 469 786Inorganic Silt and Clay 29 129 120 650 1576Silty Sand and Gravel 121 250 125 750 2185Glacial Till 25 275 140 1060 4889Weathered Rock 25 300 150 6600 203083Bedrock 150 10000 466215
2
3 Rock Motions
The rock motions are selected from New York City Seismic Guidelines (reference 3) for three different
earthquakes: (1) 500 year return period earthquake (for service limit); (2) 1500 year return period
earthquake; (3) 2500 year return period earthquake (for strength limit). For each earthquake, the
horizontal and vertical seismograms are displayed through figures 1 to 3.
4 Site Specific Design Spectrum
From the analysis of ProShake, the horizontal and vertical spectra for 5% damping at the ground
surface corresponding to each earthquake are shown from figures 4 to 6.
Per section 9.4.1.3.5 of ASCE 7-02, SDS for 2500 year return period earthquake may be deter-
mined from figure 6 as follows:
• The spectral value at the period of 0.2 sec is SDS,1 = 0.148 (g);
• The maximum spectral value at all the periods is 0.235 (g). The 90% of the peak spectral
value at any period is SDS,2 = 0.9× 0.235 = 0.212 (g);
• Therefore, SDS = max(SDS,1, SDS,2) = 0.212 (g);
Per section 9.4.1.3.5 of ASCE 7-02, SD1 for 2500 year return period earthquake may be deter-
mined from figure 6 as
SD1 = max{Sa(T = 1sec), 2Sa(T = 2sec)} = max{0.160, 2× 0.120}(g) = 0.24(g)
4 SITE SPECIFIC DESIGN SPECTRUM 3
(a) Horizontal component
(b) Vertical component
Fig. 1: Rock motions for 500 return period earthquake
4
(a) Horizontal component
(b) Vertical component
Fig. 2: Rock motions for 1500 return period earthquake
4 SITE SPECIFIC DESIGN SPECTRUM 5
(a) Horizontal component
(b) Vertical component
Fig. 3: Rock motions for 2500 return period earthquake
6
(a) Horizontal component
(b) Vertical component
Fig. 4: Site Specific Design Spectrum for 500 return period earthquake
4 SITE SPECIFIC DESIGN SPECTRUM 7
(a) Horizontal component
(b) Vertical component
Fig. 5: Site Specific Design Spectrum for 1500 return period earthquake
8
(a) Horizontal component
(b) Vertical component
Fig. 6: Site Specific Design Spectrum for 2500 return period earthquake
5 REFERENCE 9
5 Reference
1. Shear Wave Velocity Survey, The Olmsted Center, Corona Park Queens (Flushing), New York.
Hager-Richter Geoscience, Inc., October, 2009.
2. Subsurface Investigation and Analysis, Proposed Olmsted Center Building Addition, Olmsted
Center, Queens (Flushing), New York. Richard S. Kessler, September, 2009.
3. New York City Seismic Guidelines, NYC DOT 2004.