Welding

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J-2

EXAMPLE J.1 Given:

FILLET WELD IN LONGITUDINAL SHEAR

A ¼-in. × 18-in. wide plate is fillet welded to a a-in. plate. The plates are ASTM A572 Grade 50 andhave been properly sized. Use 70-ksi electrodes. Note that the plates would normally be specified as ASTM A36, but Fy = 50 ksi plate has been used here to demonstrate the requirements for long welds.Verify the welds for the loads shown.

Solution: From Chapter 2 of ASCE/SEI 7, the required strength is: LRFD Pu = 1.2(33.0 kips) + 1.6(100 kips) = 200 kips Maximum and Minimum Weld Size Because thethickness of the overlapping plate is ¼ in., the maximum fillet weld size that can be used without special notation per AISC Specification Section J2.2b, is a x-in. fillet weld. A x-in. fillet weldcan be deposited in the flat or horizontal position in a single pass (true up to c-in.). From AISC Specification Table J2.4, the minimum size of fillet weld, based on a material thickness of 4 in. is 8in. Length of Weld Required The nominal weld strength per inch of x-in. weld, determined from AISC Specification Section J2.4(a) is: Rn = FnwAwe = (0.60 FEXX)(Awe) = 0.60(70 ksi) x in. = 5.57 kips/in.(Spec. Eq. J2-4)
2

ASD Pa = 33.0 kips + 100 kips = 133 kips

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Design Examples V14.0 AMERICAN INSTITUTE OF STEEL CONSTRUCTION

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J-3

LRFD

Pu 200kips = φRn 0.75 ( 5.57 kips/in.) = 47.9 in. or 24 in. of weld on each side

Pa Ω 133 kips ( 2.00 ) = Rn 5.57 kips/in. = 47.8 in. or 24 in. of weld on each side

ASD

From AISC SpecificationSection J2.2b, for longitudinal fillet welds used alone in end connections of flat-bar tension members, the length of each fillet weld shall be not less than the perpendicular distance between them.
24 in.≥ 18 in.

o.k.

From AISC Specification Section J2.2b, check the weld length to weld size ratio, because this is an end loaded fillet weld.
L 24 in. = w x in. = 128 > 100. therefore, AISC...