(PL + PT )n s ≥ Psy

(Eq 3-21)

10. PANEL ANCHORS. Panel anchors must be installed on both sides of the shear panel columns

because the columns by themselves have inadequate shear capacity. Furthermore, if the column were

simply fastened to the track, the track would be loaded in bending, due to uplift. The track is very weak in

bending and this would violate the guidance stated in Paragraph 6c. Therefore, anchors consisting of

angle iron sections shall be welded to both sides of the column at both the top and bottom of the columns

to provide the required panel anchorage. Loose steel plates are laid over the horizontal portion of the

angle sections. The angles and plates shall be drilled with through holes and anchored to the supporting

diaphragm above and below the shear panel using embedded anchor bolts. See Appendix D (Figures D4

through D9) for examples of this anchor configuration.

a. Anchor Shear Capacity. Columns have insufficient shear capacity by themselves, and require

additional shear capacity from their anchorage detail. This will require the installation of angle iron

anchors on both sides of the columns, such that one leg of the angle extends beyond the critical shear

plane. For screwed fastener connections, the critical shear plane is along the horizontal row of screws

closest to the track in the diagonal strap-to-column connection. For the welded connections, the critical

shear plane is along the strap-to-column weld near the track. The angle iron anchor shear design

strength, VA for a single angle is defined as follows:

VA = 0.6φ vFAy bc t A

(Eq 3-22)

Where:

φv = 1.0.

FAy = the anchor angle iron yield strength.

bc = the width of the angle, which equals the out-of-plane width of the column.

tA = the thickness of the angle.

The total design shear strength, VT must exceed the maximum shear panel horizontal seismic force Phumax

expressed as:

VT = VC + 2VA ≥ Phu max

(Eq 3-23)

Where:

VC = the column shear capacity determined in according to Equation C-46 in Appendix C.

W

Phu max = Ω 0 QE = Fsu max n sb s t s

(Eq 3-24)

H +W

2

2

b. 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. This load condition is expressed by

Equation C-18.

The selected angle and plate anchors shall resist the applied shear and uplift forces. These anchors will

also provide limited moment resistance. The angles and plates will yield in flexure between the anchor

bolts and bend in the angle, but will not fail in a brittle manner. This limited moment resistance will slightly

widen the hysteretic envelope in the load deflection performance of the panel. The angles and plates can

yield significantly through many cycles with no loss of shear and uplift resistance (some loss of moment

resistance). The maximum weld thickness to the column shall be used, which is based on the thickness

of the column material, as indicated in Table 3-3. The panel anchors shall be constructed using angle

3-12

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