# Single Angles Flexural Design per AISC 360-16 with ideCAD

**How does ideCAD calculate the flexural strength for single angle members according to AISC 360-16?**

The flexural strength of steel elements is calculated automatically according to

**AISC 360-16**.

The nominal flexural strength limit states are controlled automatically according to

**AISC 360-16**.

For design members for flexure, sections are automatically classified as compact, noncompact, or slender-element sections, according to

**AISC 360-16**.

**Symbols**

**A****:** cross-sectional area of angle, in.^{2} (mm^{2})**b****:** width of leg, in. (mm)**C _{b}**

**:**The lateral-torsional buckling modification factor

**E****:**Modulus of elasticity of steel = 29,000 ksi (200 000 MPa)

**F**_{y}**:**Specified minimum yield stress of the type of steel being used, ksi

**L**_{b}**:**Length between points that are either braced against lateral displacement of the compression flange or braced against twist of the cross-section, in. (mm)

**M**_{cr}**:**The elastic lateral-torsional buckling moment

**M**_{n}**:**The nominal flexural strength

**M**_{y}**:**Yield moment about the axis of bending, kip-in. (N-mm)

*: elastic section modulus to the toe in compression relative to the*

**S**_{c}**bending axis**, in.

^{3}(mm

^{3}).

**t****:**thickness of angle leg, in. (mm)

**β**_{w}**:**section property for single angles about major principal axis, in. (mm).

The nominal flexural strength, *M _{n}*, should be the lower value obtained according to the limit states of yielding (plastic moment), lateral torsional buckling, and leg local buckling.

The nominal flexural strength of single-angle members is calculated by considering the geometric axis and principal-es cross-sectional properties. Only the limit states of yielding and leg local buckling apply for bending about the minor principal axis.

**Yielding Limit State**

**Lateral Torsional Buckling Limit State**

The nominal flexural strength, *M _{n}*, for single angles without continuous lateral-torsional restraint along the length is calculated as shown below.

The elastic lateral-torsional buckling moment, *M _{cr}*, for bending about the major principal axis of single angles is calculated as shown below.

The elastic lateral-torsional buckling moment, *M _{cr}*, for bending about one of the geometric axes of an equal leg angle with no axial compression of single angles is calculated as shown below.

With no lateral-torsional restraint:

With maximum compression at the toe,

*M*is calculated as shown below._{cr }

With maximum tension at the toe,

*M*is calculated as shown below._{cr }

*M _{y}* should be taken as 0.80 times the yield moment calculated using the geometric section modulus.

With lateral-torsional restraint at the point of maximum moment only:

The elastic lateral-torsional buckling moment, *M _{cr}*, is calculated as 1.25 times

*M*computed using Equations F10-5a or F10-5b.

_{cr}*M*should be calculated using the geometric section modulus as the yield moment.

_{y}**Leg Local Buckling Limit State**

The limit state of leg local buckling does not apply when the toe of the leg is in compression with compact section in compression.

The nominal flexural strength,

*M*, is calculated as shown below for sections with noncompact legs_{n}

The nominal flexural strength,

*M*, is calculated below for sections with slender legs._{n}