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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.