AISC 360-22

AISC 360-22 Table J2.4 | Minimum Size of Fillet Welds

If a weld bead is too small relative to the thickness of the steel plates being connected, the heavy steel pulls heat out of the weld too quickly (quenching). This makes the weld brittle and causes cracking along the weld toe. Table J2.4 establishes mandatory minimum weld leg sizes.

Code Equation

Governing Formula

w_{\min} = \begin{cases} 1/8\text{ in (3 mm) } & \text{ for } t \le 1/4\text{ in (6 mm) } \\[4pt] 3/16\text{ in (5 mm) } & \text{ for } 1/4 < t \le 1/2\text{ in (13 mm) } \\[4pt] 1/4\text{ in (6 mm) } & \text{ for } 1/2 < t \le 3/4\text{ in (19 mm) } \\[4pt] 5/16\text{ in (8 mm) } & \text{ for } t > 3/4\text{ in (19 mm) } \end{cases}

Standard: AISC 360-22Dual US Customary & SI Metric

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Notation & Variables

w_{\min}

Minimum leg size of fillet weld

in or mm

t

Thickness of the thinner part joined

in or mm

Worked Example

Identify parts joined

Connecting a 1/2" shear tab plate to a W14x90 column flange (tf = 0.710").

Find thinner part thickness

The thinner part joined is the shear tab: t = 1/2 in (0.500").

Look up Table J2.4

For 1/4 < t ≤ 1/2 in, the minimum weld leg size is 3/16 in (5 mm).

Governing Criteria

When does this govern?

Governs detailing on lightly loaded connections joining thick steel plates, column base plates, and stiffener plates.

Common Pitfall

Common Mistake

Using the thicker part joined to determine the minimum weld size. Table J2.4 is explicitly governed by the thinner part joined.

Related Resources

AISC 360-22

AISC 360-22 Table J2.4 | Minimum Size of Fillet Welds

Code Equation

Governing Formula

w_{\min} = \begin{cases} 1/8\text{ in (3 mm) } & \text{ for } t \le 1/4\text{ in (6 mm) } \\[4pt] 3/16\text{ in (5 mm) } & \text{ for } 1/4 < t \le 1/2\text{ in (13 mm) } \\[4pt] 1/4\text{ in (6 mm) } & \text{ for } 1/2 < t \le 3/4\text{ in (19 mm) } \\[4pt] 5/16\text{ in (8 mm) } & \text{ for } t > 3/4\text{ in (19 mm) } \end{cases}

Standard: AISC 360-22Dual US Customary & SI Metric

Interactive Studio

Check Automatically

AXIS verifies AISC 360-22 limits directly inside your models with full step-by-step math.

Open Calculator →

Notation & Variables

w_{\min}

Minimum leg size of fillet weld

in or mm

t

Thickness of the thinner part joined

in or mm

Worked Example

Identify parts joined

Connecting a 1/2" shear tab plate to a W14x90 column flange (tf = 0.710").

Find thinner part thickness

The thinner part joined is the shear tab: t = 1/2 in (0.500").

Look up Table J2.4

For 1/4 < t ≤ 1/2 in, the minimum weld leg size is 3/16 in (5 mm).

Governing Criteria

When does this govern?

Governs detailing on lightly loaded connections joining thick steel plates, column base plates, and stiffener plates.

Common Pitfall

Common Mistake

Using the thicker part joined to determine the minimum weld size. Table J2.4 is explicitly governed by the thinner part joined.