Building Design and Construction Handbook - Merritt - Ventech!

TABLE 7.27 Design Shear Strength for Welds, ksi*
Types of weld and stress Material
STRUCTURAL STEEL CONSTRUCTION 7.95
The effective throat thickness of a fillet weld is the shortest distance from the
root of the joint to the nominal face of the weld (Fig. 7.3). For fillet welds made
by the submerged-arc process, however, the effective throat should be taken as the
leg size for welds 3 ⁄8 in and smaller but as the theoretical throat plus 0.11 in for
larger fillet welds.
For a complete-penetration groove weld, the effective throat is the thickness of
the thinnest part joined. For partial-penetration groove welds, the effective throat
thickness depends on the included angle at the root of the groove. For all J or U
joints and for bevel or V joints with an included angle of 60� or more, the effective
throat thickness may be taken as the depth of the chamfer. When the included angle
for bevel or V joints is between 45� and 60�, the effective throat thickness should
be the depth of chamfer minus 1 ⁄8 in. For flare bevel and flare V-groove welds when
flush to the surface of a bar or a 90� bend in a formed section, the effective throat
thickness is 5 ⁄6 and 1 ⁄2 the radius of the bar or bend, respectively. When the radius
is 1 in or more, for gas metal arc welding, the effective thickness is 1 ⁄4 the radius.
Welds subject to static loads should be proportioned by ASD for the allowable
stresses and by LRFD for the design strengths in Table 7.27. If connections will
Resistance
factor �
Complete penetration groove weld
LRFD
Nominal strength†
F BM or F w
ASD
Allowable stress
Tension normal to effective area Base 0.90 F y Same as base metal
Compression normal to effective area Base 0.90 F y Same as base metal
Tension or compression parallel to axis of weld
Shear on effective area Base 0.90 0.60F y 0.30 � nominal tensile strength
of weld metal
Weld electrode 0.80 0.60F EXX
Partial penetration groove welds
Compression normal to effective area
Tension or compression parallel to axis of weld†
Shear parallel to axis of weld
Base
Base
Weld electrode
0.90 Fy Same as base metal
0.75 0.60FEXX 0.30 � nominal tensile strength
of weld metal
Tension normal to effective area Base 0.90 Fy 3.0 � nominal tensile strength
of weld metal
Weld electrode 0.80 0.60FEXX Fillet welds
Shear on effective area Base
Weld electrode
Tension or compression parallel to axis of
weld†
Base 0.90 Fy Shear parallel to faying surfaces (on effective
area)
Base
Weld electrode
Plug or slot welds
0.75 0.60F EXX 0.30 � nominal tensile strength
of weld metal
0.75 0.60F EXX 3.0 � nominal tensile strength
of weld metal
* Reprinted with permission from F. S. Merritt and R. L. Brockenbrough, ‘‘Structural Steel Designers Handbook,’’
2d ed., McGraw-Hill, Inc., New York.
† Design strength is the smaller of F BM and F u:
F BM � nominal strength of base metal to be welded, ksi.
F w � nominal strength of weld electrode material, ksi.
F y � specified minimum yield stress of base metal, ksi.
F EXX � classification strength of weld metal, as specified in appropriate AWS specification, ksi.