Page 160 - Structural Steel Designers Handbook AISC, AASHTO, AISI, ASTM, and ASCE-07 Design Standards

Brockenbrough_Ch03.qxd 9/29/05 5:05 PM Page 3.92

CONNECTIONS

3.92 CHAPTER THREE

WEB CRIPPLING (UNDER NORMAL LOAD H C )

  24 5 .  129  15 .  29 000 50 2 07
×
.
,
× .
×
+

2
.
φR wcp = 0 75 0 8 . ×1 2913  
.
   16 7 .  207   129
.
.
>
= 4820 kips 220 kips OK
WEB SHEAR. The horizontal force, H c , is transferred to the column by the gusset-to-column con-
nection and back into the beam by the beam-to-column connection. Thus, the column web sees H c =
220 kips as a shear. The column shear capacity is
φR v = 0.9 × 0.6 × 50 × 1.29 × 16.7 = 583 kips > 200 kips OK
Gusset-to-Beam Connection. Design for 349 kips shear and 4205 in⋅kips moment.
GUSSET STRENGTH. Design strength for the gross section shear is
f v = 349/(1.5 × 30) = 7.76 ksi < 19.4 ksi OK
Design strength for flexure is
2
f b = (4205 × 4)/(1.5 × 30 ) = 12.5 ksi < 32.4 ksi OK
WELD OF GUSSET-TO-BEAM FLANGE
.
f peak = 776 2 +125 . 2 × 15 . = 11 0 . kips/in
2
θ = atan  12 5 .  = 58 2 . °
w
.
 776 
1 ] 15 .
f ave = [ 776 2 +125 . 2 + 776 2 +125 . 2 = 11 0 . kips/in
.
.
2 2
Since 11.0/11.0 = 1.0 < 1.25, the weld size based on the average force in the weld is 1.25f ave .
Therefore,
.
D = 11 0 . ×1 25 = 710
.
.
15
.
1 392 1 [ + 0 5 . sin ( 58 2 . )]
1
Use a / 2-in fillet weld.
Beam Web
WEB YIELD. Although there is no axial component, the couple M B = 4205 in⋅kips is statically
equivalent to equal and opposite vertical shears at a lever arm of one-half the gusset length or 15 in.
The shear is thus
V = 4205 = 280 kips
s
15
This shear is applied to the flange as a transverse load over 15 in of flange. It is convenient for analy-
sis purposes to imagine this load doubled and applied over the contact length N = 30 in. The design
web yielding strength is
φR wy = 1.0 × 50 × 0.47(30 + 5 × 1.27) = 854 kips > 280 × 2 = 560 kips OK

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