APPENDIX D

SEISMIC DESIGN EXAMPLE

(English I-P units only)

D1. EXAMPLE DESIGN PROBLEM. An example problem is presented here to demonstrate the

design process presented in Chapter 3 and Appendix C. Shear panels will be designed in the short

direction of the building only to illustrate the design process. In an actual building the lateral load

resisting system must be designed in both directions. This example is a barracks-type building that

will be designed for construction at Fort Lewis, located between Tacoma and Olympia, Washington.

This building is similar to a Prototype 3 Story Steel Stud Framed Barracks Building for Seismic Zones

0 21. The reader will be referred to tabular data and equations presented in Chapter 3 and

Appendix C. When needed, FEMA 302 guidance will be referenced.

The barracks building has a Seismic Use Group of I (FEMA 302, 1.3), which gives it an Occupancy

Importance Factor, I, of 1.0 (see Table C-1).

D2. GROUND MOTION DEFINITION. The maximum considered earthquake ground motions are

determined from spectral response acceleration Maps 9 and 10 (for the Pacific Northwest). The

acceleration for 1 second, S1, is 0.39 g (Map 10). Table D-1 summarizes these values. These

values are determined by interpolating between the map contours for the Fort Lewis location. The

soil conditions are unknown, so a reasonable worst-case site classification of D is used. Values of

Site Coefficients, Fa and Fv, are calculated based on straight-line interpolation from the values in

Tables C-2a and C-2b, and are shown in Table D-1. Values for the maximum considered earthquake

effects, are calculated using Equations C-1 and C-2, and are shown in Table D-1. Design earthquake

Equations C-3 and C-4, and are shown in Table D-1.

Importance Factor, I

1.0

Short Period Spectral Response Acceleration, SS

1.2 g

1 Second Spectral Response Acceleration, S1

0.39 g

Site Classification

D

Site Coefficient, Fa

1.02

Site Coefficient, Fv

1.62

Adjusted Short Period Spectral Response Acceleration, SMS

1.22 g

Adjusted 1 Second Spectral Response Acceleration, SM1

0.63 g

Design Short Period Spectral Response Acceleration, SDS

0.82 g

Design Short Period Spectral Response Acceleration, SD1

0.42 g

T0

0.103 seconds

TS

0.516 seconds

Assumed Design Spectral Response Acceleration, Sa

0.82 g

Seismic Design Category

D

Response Modification Factor, R

4

Deflection Amplification Factor, Cd

3.5

A design response spectrum is developed from these terms, as described in Appendix C, Paragraph

C2, using Equations C-5 and C-6, and plotted in Figure D-1. For the natural period of the structure,

T, this spectrum defines values of effective acceleration. The natural period of the barracks building,

T, will almost certainly fall between T0 and TS, defined in Appendix C, Paragraph C2, so that the

1

U.S. Army Corps of Engineers Barracks Prototype Department of the Army, for the National Association of Architectural Metal

Manufactures (NAAMM), by Matsen Ford Design, Drawings Dated 1/3/97.

D-1

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