Page 49 - Handbook of Structural Steel Connection Design and Details

Fasteners and Welds for Structural Connections

34 Chapter One

PJP

t e
<
120° < Φ = 150°
o

t e
Figure1.17 Acute angles less
than 60° and obtuse angles
greater than 120°.
<
30° = Φ < 60°
o

penetration (PJP) groove weld (Fig. 1.17) and the effective throat, t ,
e
decreases due to the allowance, z, for the unwelded portion at the root. While
this allowance varies based on the welding process and position, it can con-
servatively be taken as the throat less ⁄8 in for 60 to 45° and less ⁄4 in for 45 to
1
1
30°. Joints less than 30°are not prequalified and generally should not be used.
1.3.8 Obliquely loaded concentric
fillet weld groups

The strength of a fillet weld is dependent on the direction of loading.
Welds that are loaded in their longitudinal direction have a design
strength of 0.6F , while welds loaded transverse to their longitudinal
EXX
axis have a design strength 1.5 times greater. The strength of welds
loaded between these extremes can be found as

.
.
F = 06 F ( 10 +050 sin 15 ) θ
.
.
w EXX
This equation is easily applied to a single-line weld, or a group of
parallel-line welds, but when applied to weld groups containing welds
loaded at differing angles, such as that given in Fig. 1.18, its applica-
tion becomes much more complex. In such cases, deformation compati-
bility must also be satisfied. Since the transversely loaded welds are
considerably less ductile than the longitudinally loaded welds, the trans-
versely loaded welds will fracture before the longitudinally loaded welds
reach their full capacity. This can easily be seen by examining Fig. 1.19
(taken from Fig. 8-5 AISC 2005). A weld loaded transverse to its longitu-
dinal direction will fracture at a deformation equal to approximately 0.056

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