The connection passes all limit states. By inspection it is seen that this connection is adequate for all
of the beam-to-column connections, including the mezzanine edge beam-to-column connection.
Gusset plates
Single Gusset
-
Weld of brace-to-plate: The welds are to be designed to have a capacity greater than the tension
capacity of the brace. This is not required by the AISC Seismic Provisions for ordinary
concentrically braced frames but is used to be conservative since the brace tensile strength is higher
than the demand from Ω 0QE.
Tensile strength of the brace = RyFyAg
AISC Seismic Provisions Sec. 14.3.a
Tensile strength = 1.5(36)(2.23) = 120.4 kips (536 KN)
Assume E70 welds and " (13 mm) thick gusset plate
Minimum weld size = 3/16" = 0.188" (4.78mm)
AISC LRFD Table J2.4
Maximum weld size = thickness of welded material for materials less than " in thickness; the brace
has a wall thickness of 0.216" (5.49mm). Use a weld size of 3/16" (4.78mm)
Design strength of weld:
φ .6(FEXX) = 0.75(0.6)(70) = 31.5 ksi (217 N/mm2)
0
AISC LRFD Table J2.5
φ n = (31.5 ksi)(0.707)(3/16")(length) = 4.18 kips / inch (11.34 N/mm2 per cm. of weld) (controls)
R
Design strength of base material (based on pipe)
φ UBMABM = 0.75(0.6)(58)(0.216")(length) = 5.64 kips / inch (15.31 N/mm2 per cm. of weld)
F
Length = 120.4 kips / (4.18 kips / inch) = 28.8 inch (73.2 cm)
Use 3/16" (4.78 mm) fillet welds, 8" (20.3 cm) long along each edge of pipe
-
Tension rupture of plate: The tension rupture strength of the plate is based on Whitmore' area. This
s
area is calculated as the product of the plate thickness times the length W, shown in the sketch as a 30
degree angle offset from the connection line. The tension rupture strength of the plate is designed to
exceed the tensile strength of the brace, 120.4 kips.
W = 2(8"*tan 30) + 3.5" = 12.7" (32.26 cm)
φPn = φFuAe = 0.75(58)(12.7")(0.5") = 276 k (1228 KN)> 120.4 k (536 KN) AISC LRFD Eq. D1-2
t
t
H1-58
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