CEMP-E
TI 809-26
1 March 2000
with a phi of 0.8.
(5) CJP groove welds and other welds carrying tension or compression parallel to the axis of the
weld need not be designed for the tensile or compressive stress, only for any shear forces that may be
transferred between the connected parts. As an example, girder web-to-flange welds need not be
designed for the axial force from bending, only for the shear transferred between the web and flange.
(6) PJP groove welds in transverse tension are permitted to carry 0.60 times the classification
strength of the filler metal, with a phi of 0.8. The stress on the base metal is also limited to the minimum
specified yield strength of the base metal, with a phi of 0.90, using the effective size (throat) of the
groove weld for the check of the base metal stress.
(7) PJP groove welds in compression are currently treated differently by AWS and AISC. Under
AWS D1.1, PJP groove welds are categorized into joints designed to bear and joints not designed to
bear. AISC, because it is based upon new construction, provides design values only for the joint
designed to bear application. Under AISC, for joints designed to bear, the weld stress need not be
checked, as the base metal will govern the strength of the joint, with a phi of 0.9.
(8) For joints not designed to bear, only AWS provides design values, based upon Allowable
Stress Design (ASD). The weld stress may not exceed 0.50 times the classification strength of the filler
metal, and the base metal stress may not exceed 0.60 times the minimum specified yield strength of the
base metal, applied to the throat of the groove weld. LRFD values, considering the factor phi, are
generally 1.5 times the ASD values.
(9) PJP groove welds in shear may be stressed to 0.60 times the classification strength of the filler
metal, with a phi of 0.75.
(10) Fillet welds may be stressed to 0.45 times the classification strength of the filler metal, with a
phi of 0.75. There is no need to check the shear stress in the base metal along the diagrammatic leg of
the fillet weld. Research indicates that, because of penetration and HAZ hardening, the leg of the fillet
weld is not a failure plane that needs checked.
(11) For transversely loaded fillets welds, AWS D1.1 Section 2.14.4 and 2.14.5, and AISC LRFD
Specification Appendix J2.4, permit a 50% increase in the allowable shear stress on the weld. For angles
other than transverse, an increase is also permitted based upon an equation. For eccentrically loaded
fillet weld groups, allowable shear stress increases are also permitted when using the instantaneous
center of rotation approach for the analysis of the weld group. Design values for typical weld groups are
provided in the AISC Manual.
(12) When fillet weld strength increases, as above, are used for loading other than parallel to the
weld axis, AISC LRFD Specification Table J2.5, Note [h] requires the use of CVN toughness as above.
(13) When a fillet weld is loaded longitudinally along its axis, and is loaded from its end, as in a
splice plate or brace member, there is a maximum effective length of 100 times the leg size before a
reduction factor must be implemented. Longer fillet welds loaded in such a manner must be analyzed
using a reduction coefficient Beta from AISC LRFD Specification equation J2-1. The maximum effective
length is 180 times the leg size, which would apply when the weld is 300 times the leg size in length, with
a reduction coefficient Beta of 0.6.
(14) Plug and slot welds may be stressed to 0.60 times the classification strength of the filler metal,
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