AISC 360-22, Specification for Structural Steel Buildings
Last Updated 29 Oct 2026
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For limitations on the longitudinal spacing of connectors between elements in continuous contact consisting of a plate and a shape, or two plates, see Section J3.6.
Lacing, perforated cover plates, or tie plates without lacing are permitted to be used on the open sides of built-up tension members. Tie plates shall have a length not less than two-thirds the distance between the lines of welds or fasteners connecting them to the components of the member. The thickness of such tie plates shall not be less than one-fiftieth of the distance between these lines. The longitudinal spacing of intermittent welds or fasteners at tie plates shall not exceed 6 in. (150 mm).
User Note: The longitudinal spacing of connectors between components should preferably limit the slenderness ratio in any component between the connectors to 300.
TABLE D3.1Shear Lag Factors for Connections to Tension Members
Case
Description of Element
Shear Lag Factor, U
Examples
1
All tension members where the tension load is transmitted directly to each of the cross-sectional elements by fasteners or welds (except as in Cases 4, 5, and 6).
U = 1.0
-
2
All tension members, except HSS, where the tension load is transmitted to some but not all of the cross-sectional elements by fasteners or by longitudinal welds in combination with transverse welds. Alternatively, Case 7 is permitted for W, M, S, and HP shapes and Case 8 is permitted for angles.
U = 1 - x̄/l
[IMAGE]
3
All tension members where the tension load is transmitted only by transverse welds to some but not all of the cross-sectional elements.
U = 1.0 and An = area of the directly connected elements
-
4[a]
Plates, angles, channels with welds at heels, tees, and W-shapes with connected elements, where the tension load is transmitted by longitudinal welds only. See Case 2 for definition of x̄.
U = 3l2 / (3l2 + w2) (1 - x̄/l)
[IMAGE]
5
Round and rectangular HSS with single concentric gusset through slots in the HSS.
x̄ = Rsinθ / θ - 1/2 tp θ in rad U = [1 + (x̄/l)3.2]-10
[IMAGE]
x̄ = b - (2b2 + tH - 2t2) / (2H + 4b - 4t) U = 1 - x̄/l
[IMAGE]
6
Rectangular HSS with two side gusset plates.
U = (B UB + H UH) / (H + B) UB = 3l2 / (3l2 + B2) UH = 3l2 / (3l2 + H2)
[IMAGE]
BDHdlwxˉ= overall width of rectangular HSS member, measured 90∘ to the plane of the connection, in. (mm) = outside diameter of round HSS, in. (mm) = overall height of rectangular HSS member, measured in the plane of the connection, in. (mm) = depth of section, in. (mm); for tees, d= depth of the section from which the tee was cut, in. (mm) = length of connection, in. (mm) = width of plate, in. (mm) = eccentricity of connection, in. (mm)
[a] l=2l1+l2, where l1 and l2 shall not be less than 4 times the weld size.
TABLE D3.1 (continued)Shear Lag Factors for Connections
to Tension Members
Case
Description of Element
Shear Lag Factor, U
Examples
7
W-, M-, S-, or HP-shapes, or tees cut from these shapes. (If U is calculated per Case 2, the larger value is permitted to be used.)
with flange connected with three or more fasteners per line in the direction of loading
bf ≥ 2/3d, U = 0.90 bf < 2/3d, U = 0.85
–
with web connected with four or more fasteners per line in the direction of loading
U = 0.70
–
8
Single and double angles. (If U is calculated per Case 2, the larger value is permitted to be used.)
with four or more fasteners per line in the direction of loading
U = 0.80
–
with three fasteners per line in the direction of loading (with fewer than three fasteners per line in the direction of loading, use Case 2)
U = 0.60
–
BDHdlwxˉ= overall width of rectangular HSS member, measured 90∘ to the plane of the connection, in. (mm) = outside diameter of round HSS, in. (mm) = overall height of rectangular HSS member, measured in the plane of the connection, in. (mm) = depth of section, in. (mm); for tees, d= depth of the section from which the tee was cut, in. (mm) = length of connection, in. (mm) = width of plate, in. (mm) = eccentricity of connection, in. (mm)
[a] l=2l1+l2, where l1 and l2 shall not be less than 4 times the weld size.