Design of gusset-to-column flange and beam web weld;
This connection requires a weld length greater than the column flange. The plate must be welded to both the column
flange and the beam web to develop the brace force.
Design weld capacity to be greater than horizontal component of brace capacity = (0.707)(238) = 168 kips (747 KN)
Column flange thickness = 0.86 in. (21.8mm)
Beam web thickness = 0.31"
Minimum weld size = " (6.35mm)
(AISC LRFD Table J2.4)
Maximum weld size = beam web thickness ≈0.25" (6.35 mm)
Use 1/4" (6.35 mm) welds
Strength of weld; (per AISC LRFD Sec. J.4 and Table J2.5)
Weld material: φ nw = φte) (0.6 FEXX) = 0.75(0.6)(70ksi)(0.707)(0.25) = 5.57 kips / inch (0.98 KN/mm) (governs)
R
(
Base material: φ nw = φ0.6Fu) = (0.75)(0.31")(0.6)(58) = 8.1 kips / in (1.42 KN/mm)
R
(
Length of weld required = 168 k / (5.57 k/") = 30.16" (76.6 cm) (2 welds at connection weld 16" (40.64 cm) long =
32" > 30.16")
Use 1/4" (6.35mm) fillet welds on top and bottom of plate.
Design member to develop force into shear wall
Vertical component = (0.707)(238k) = 168 kips (747 KN)
Use 6 x 6 x angle to develop forces; Assume 7/8" anchor bolts to concrete shear wall
Check gross section yielding; Pu = φFyAg = (0.9)(36)(5.75) = 186 kips (827 KN) > 168 kips (747 KN)
t
Check net section fracture; Pu = φFuAe = (0.75)(58)(0.85)(5.75 (7/8+1/16)(0.5)) = 195 kips (867 KN) > 168 kips
t
Design weld of plate to angle
Minimum weld size = " (6.35mm)
(AISC LRFD Table J2.4)
Maximum weld size = plate thickness 1/16" = 0.5-1/16 = 0.44" (11.18mm)
Use 7/16" (11.11 mm) welds (0.438")
Strength of weld; (per AISC LRFD Sec. J.4 and Table J2.5)
Weld material: φ nw = φte) (0.6 FEXX) = 0.75(0.6)(70ksi)(0.707)(0.438) = 9.75 kips / inch (1.71 KN/mm)
R
(
(governs)
Base material: φ nw = φ0.6Fu)t = (0.75)(0.5")(0.6)(58) = 13.05 kips / in (2.29 KN/mm)
R
(
Length of weld required = 168 k / (9.75 k/") = 17.23" (43.8 cm) (2 welds at connection, weld for 16" on both sides
of plate. Total length = 2 x 16 = 32" (81.3 cm) > 17.23" (43.8 cm), OK
Use 16" long (81.3 cm) 7/16" (11.11mm) fillet welds along top and bottom of plate.
Design bolts for angle to wall connection.
Design per FEMA 302
Tensile strength of bolts:
-Assume 7/8" diameter bolts @ 12"o/c with a 6" embedment length
H3-59
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