Page 286 - Handbook of Structural Steel Connection Design and Details

Welded Joint Design and Production

Welded Joint Design and Production 271

greatly increasing the portion of the column participating in the trans-
fer of moment. Significant experience was gained utilizing the haunches
for the repairs of the SAC-sponsored tests.
Reduced beam section connections. In this configuration, the cross sec-
tion of the beam is intentionally reduced within a segment to produce a
deliberate plastic hinge within the beam span, away from the column
face. One variant of this approach produces the so-called dog-bone profile.
Reduced section details offer the prospect of a low-cost connection
and increased performance out of detailing that is very similar to the
pre-Northridge connection. Control of material properties of the beam
will still be a major variable if this detail is used. Lateral bracing will
probably be required in the area of the reduced section to prevent buck-
ling, particularly at the bottom flange when loaded in compression.
Partially restrained connections. Several engineers and researchers
have suggested that partially restrained connection details will offer
a performance advantage over the special moment-resisting frames.
The relative merits of a partially restrained frame versus a rigid
frame are beyond the scope of this chapter. However, many engineers
immediately think of bolted PR connections when it is possible to uti-
lize welded connections for PR performance as well.
Illustrated in Fig. 3.37 are a variety of details that can be employed
utilizing the PR concept. Detailing rules must be developed, and testing

L

w

Butt weld
Fillet weld
M
F =
d b
d b

Figure 3.37 Examples of partially restrained connection details. (Courtesy
of The Lincoln Electric Company.)

Downloaded from Digital Engineering Library @ McGraw-Hill (www.accessengineeringlibrary.com)
Copyright © 2009 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.