| 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.
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.