Page 131 - Structural Steel Designers Handbook AISC, AASHTO, AISI, ASTM, and ASCE-07 Design Standards

Brockenbrough_Ch03.qxd 9/29/05 5:05 PM Page 3.63

CONNECTIONS

CONNECTIONS 3.63

Note that the prying lever arm is controlled by the narrower of the two flanges.

.
.
.
b ′ = 2 073 − 0 875 = 1 636 in
2
.
.
a ′ = 1 3125 + 0 875 = 175 in
.
2
ρ = 093
.
.
p = p eff = 463 in
.
δ =− 0 9375 = 0 798.
1
463
.
.
.
t = 444 × 406 . ×1636 = 0 990 in
.
c
.
463 × 65
.
α ′ = 1    0 990  2 −  1  = 131
.
.
0 798 ×1 93   0 570  
.
.
Use α′ = 1.
The design strength of the bolt in tension is
=
.
.
T = 40 6 ×  0 570.  2 ×1 798 24 2 k > 5 96 k OK
.
.
d 
 0 990.
Web Yielding on the W18 × 50 Beam. Since 5k = 5 × 1.25 = 6.25 > p = 3 in, the web tributary to
each bolt at the k distance exceeds the bolt spacing and thus N = 9.
φR wy = 1.0 × (9 + 5 × 1.25) × 50 × 0.355 = 271 kips > 50.5 kips OK
Web Crippling on the W18 × 50 Beam. Web crippling occurs when the load is compression, thus
N = 12, the length of the W16 piece.
 .  15 .  29 000 50 0 570
×
× .
,
2
+
.

× .
× .
φR wcp = 0 75 0 80 0 355 13  12  0 355 
.
  18 0 .  0 570   0 355
.
= 229 kips > 50 5 . kips OK
This completes the design calculations for this connection. A load path has been provided through
every element of the connection. For this type of connection, the beam designer should make sure
that the bottom flange is stabilized if P can be compressive. A transverse beam framing nearby as
shown in Fig. 3.36 by the W18 × 50 web hole pattern, or a bottom flange stay (kicker) will provide
stability.
3.5.2 Column Base Plates
The geometry of a column base plate is shown in Fig. 3.37. The area of the base plate is A 1 = B × N. The
area of the pier which is concentric with A 1 is A 2 . If the pier is not concentric with the base plate, only
that portion which is concentric can be used for A 2 . The design strength of the concrete in bearing is
φ F = 06 085 f c ′ A 2 (3.58)
.
× .
cp
A 1
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2004 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.