Page 162 - Structural Steel Designers Handbook AISC, AASHTO, AISI, ASTM, and ASCE-07 Design Standards

Brockenbrough_Ch03.qxd 9/29/05 5:05 PM Page 3.94

CONNECTIONS

3.94 CHAPTER THREE

Prying action is now checked using the method and notation of the AISC Manual:
.
=
b = 55 . − 047 − 0 375 2 14 in
.
.
2
+ 47 5 5
a = 80 . − . = 149 in
.
2
Check 1.25b = 1.25 × 2.14 = 2.68 in. Since 2.68 > 1.49, use a = 1.49 in.
.
b ′ = 214. − 10 = 164 in
.
2
.
a ′ = 149 + 10 . = 199
.
2
ρ = 0 824
.
.
δ =− 125 = 0 583
.
1
3
.
.
t c = 444 × 291 . ×164 = 110 in
.
×
358
.
α ′ = 1    010  2 −  1  = 108
.
0 583 ×1 824   075  
.
.
.
The design strength per bolt, including prying, is
 075.  2
T = 29 1 1 ( + 0 583. ×1 00. )
.
d
 110. 
= 21 4. kips > 15 7 kips OK
.
In addition to the prying check, the clips should
also be checked for gross and net shear, but these will
not control in this case.
WELD OF CLIPS TO BEAM WEB. The weld is a C-
shaped weld with length l = 21 in, kl = 3.5 in, k =
3.5/21 = 0.167. From the AISC Manual, Table 8-9,
xl = 0.0220 × 21 = 0.462 in, so al = 6 − 0.462 = 5.538
in, and a = 5.538/21 = 0.264. Since tan 220/170 =
−1
52.3°, use the chart for 45°. By interpolation, C = 2.56.
A / 4-in fillet weld has a capacity of φR w = 0.75 × 2.56 ×
1
4 × 2 × 21 = 323 kips. To support this weld, the web
thickness required is 0.90 × 0.60 × 50 × t w > 1.392 ×
4 × 2. Thus, t w required ≥ 0.41 in. Since the actual
web thickness is 0.470 in, the weld is fully effective
and has the calculated capacity. Thus, since 323 kips >
220 + 170 2 = 278 kips, the / 4-in fillet weld is OK.
1
2
BENDING OF THE COLUMN FLANGE. Because of the
axial force, the column flange can bend just as the
clip angles. A yield-line analysis derived from Mann
and Morris (1979) can be used to determine an effec-
tive tributary length of column flange per bolt. The
yield lines are shown in Fig. 3.52. First, determine
the effective pitch, p eff :
FIGURE 3.52 Yield lines for flange bending.
(Source: A. R. Tamboli, Handbook of Structural Steel p + π
1
Connection Design and Details, McGraw-Hill, 1999, p = ( n − ) b + 2 a
with permission.) eff n
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