Long

Long

Number

Long Dir

Long Dir

Direction

Seismic

Dir

Height

Vertical

Frames

Lateral

Seismic

Total

Response

Base

at Floor

Distribution

in Long

Seismic

Story

Panel

Weight

Coefficient

Shear

Level

Factor

Dir

Force/frame

Shear

Level

WL

Cs

VL

hxS or hxL

CvxL

nL

FxL

VxL

(k-mass)

(g)

(kips)

(ft)

(kips)

(kips)

Roof

3rd

247

27.042

0.271

2

42.713

42.713

Cumulative

247

2nd

647

18.583

0.488

2

76.983

119.696

Cumulative

894

1st

653

9.125

0.241

2

38.110

157.806

Cumulative

1547

0.204

316

D9. DIAGONAL STRAP DESIGN. From the values of seismic story shear, Vx (Vx + Qsi in Equation 3-

4) the shear panel diagonal straps are sized according to Equation 3-4. Values of the shear panel

design strength, φQsy are given in Table D-5. Two identical shear panels are used at each floor level,

t

and applied story shear in the short direction, VxS per shear panel are shown in Table D-5. Trial

shear panel dimensions and diagonal strap sizes for each floor level are defined so that the design

strength, φQsy exceeds the applied story shear, VxS per shear panel, using the spreadsheet program

t

that models Equation 3-4. Table D-5 shows trial shear panel configurations that meet this

requirement for each floor of the critical frame in the barracks building example. All diagonal straps

require ASTM 653, Grade 33 or Grade 50 steel. Panel dimensions are based on the dimensions

given for Shearwall Type " W-3"(Interior Load-Bearing Walls) of the barracks building drawings

S

(Sheet S-6).

The diagonal straps are the sole lateral-load-resisting element, and as such they determine the story

drifts. The elastic deflections, δe, at each floor level are calculated as follows:

x

δy VxS

δe = s

(Eq D-19)

x

Qsy nS

where δy is the lateral deflection at diagonal strap yielding given by:

s

Fsy H2 + W 2

δy =

(Eq D-20)

E W

s

Values of δe are given in Table D-5, for the trial diagonal straps at each floor level in the short

x

direction of the building. The design story drifts, ∆ are the differences in deflection at the center of

mass at the top and bottom of the story under consideration. These deflections are calculated from

the elastic deflection, δe as follows (from Equation C-29):

x

Cdδe

∆=δ=

x

(Eq D-21)

x

I

Where :

Cd = the deflection amplification factor given in Table D-1 (3.5 for diagonal strap panels).

I = the importance factor given in Table D-1 (1.0 for the barracks building).

Values for the design story drifts are given in Table D-5.

D-7

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