3-23. The column shear capacity, Vc was determined in Paragraph D10e according to Equation C-

46. Table D-14 shows the yield stress, width and thickness of the angles used in these anchors, so

that the combined shear strength of the columns and angles VT exceed Phumax (Equation 3-23). Table

D-11 shows that combined shear strength VT exceeds Phumax for all the trial shear panels.

b. Shear Panel Anchor Angle and Plate Design. The most critical load condition for anchors

is when the effects of gravity load and seismic forces counteract each other, as expressed by

Equation C-18.

Column-to-angle welds and angle sizes are selected for each trial configuration based on the

guidance in Tables 3-3 and 3-4. For each case, the maximum weld thickness and angle thickness is

selected. These sizes are shown in Table D-14 and Figures D-4 through D-9. For each trial anchor,

a plate must be added as shown in Figures D-4 through D-9 (and Table D-14), to provide adequate

uplift resistance. These plates will also add moment resistance. Anchor angles and plates are

designed following the requirements of Equation 3-25, as shown in Table D-14 and D-15.

The capacity of the vertical column-to-angle welds at the corner of the columns assume double shear

(Equation C-59), because the effective thickness of this grove weld should be at least twice the

thickness of the column material. This is because of the curvature of the column corner that the

grove weld will fill. The anchor must provide moment resistance for the moment from the eccentric

loading of the diagonal strap, accounting for the maximum estimated yield overstrength of the strap

(PsymaxLs). Any moment capacity beyond this is not required (i.e., Pcb in Equation 3-31 may equal

zero), but will provide beneficial column moment resistance. However, at any load condition at least

one column will have little axial load and no diagonal strap load, so that the anchors will provide

significant moment resistance to provide some moment frame capacity in the shear panel.

Min Gravity

Anchor

Col/Anchor

Anchor Angle

Plate

Angle

Load/

Uplift @ max

Weld

Yield

Thickness Moment

Panel

Strap Yield

Thickness Stress

Size

Capacity

GLmin

Pvymax

tw

FyA HA WA

tA

tp

MA

k

(kips)

(kips)

(in)

(ksi)

(in)

(in)

(in)

(k-in)

3rd Floor

1.44

11.3

0.125

36 L 4 x 4 x 0.25 0.625 0.375

9.87

3rd Floor*

1.44

14.7

0.125

36 L 4 x 4 x 0.25 0.625 0.438

12.34

2nd Floor

6.38

34.1

0.125

36 L 4 x 4 x 0.25 0.625 0.563

18.41

1st Floor

12.21

44.9

0.125

36 L 4 x 4 x 0.25 0.625 0.688

26.01

1st Floor*

12.21

42.5

0.125

36 L 4 x 4 x 0.25 0.625 0.625

22.02

1st Floor

12.21

35.3

0.188

36 L 6 x 6 x 0.50 1.000 0.750

39.49

The panels in Rows 3 and 4 fail to meet the requirement of Equation 3-25, as can be seen in Table D-

15. Row 3 (2nd Floor shear panels) is the worst case where the column-to-angle weld design

strength, PA is 3% below the applied load, based on the maximum estimated yield stress of the

diagonal straps. This shear panel must be redesigned, which can be done by increasing the

thickness of the column material as the strength of the welds are directly proportional to the thickness

of the thinner material (see Equations C-56 and C-59). The shear panel shown in Row 5 meets the

st

st

requirement of Equation 3-25 for the 1 Floor shear panel and this panel is selected for the 1 Floor.

D-15

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