Steel Checks to AISC 360

The steel design check supports the ANSI/AISC 360-05 and 360-10 ASD and LRFD versions.

All cases provided to the checker are assumed to be factored loads including second order small p-delta effects. All cases provided to the checker are assumed to be ultimate limit state (i.e. the member forces are fully factored). Any non ULS cases – e.g. unfactored wind load – will be treated as if they are ULS, and so will result in non-conservative utilizations.

Definition

Section Classification

Section is classified as Compact, Non-compact and Slender in accordance with AISC360-05 Clause B4 and Table B4.1.

Tension

Section is checked at the ends of every sub-span of the member for the moments and forces acting on it.

Tension capacity at a section is calculated in accordance with AISC360-05 clause D2. Sections in tension uses the user defined ‘Net Area Ratio’ to compute Net Area and ‘Effective net area factor (Beta)’ to compute Effective Net Area.

Compression

Compression force is checked in accordance with AISC360-05 Chapter E. Checker uses appropriate equations depending upon the section shape and local buckling class. Effective length factor for the members under compression is taken in accordance with the AISC360-05 Table C-C2.2.

Bending

Section is checked for bending in accordance with AISC360-05 Chapter F using appropriate equations.

If the member has an Equivalent Uniform Moment Factor override specified, this is used in place of in lateral torsional buckling calculations.

Shear

Shear is checked according to AISC360-05 Chapter G using appropriate equations. While calculating the shear strength steel checker assumes that the section web is unstiffened.

Torsion

At present, any significant torsional moment (greater than 5% of the torsional capacity) causes a warning.

Interaction checks

The section is checked against all the applied forces in accordance with AISC360-05 Clause H1 and H2. Any torsion on the section is ignored from the interaction checks.

Moments used in the interaction check includes the moments due to eccentricity in axial force. Eccentricity may be due to end connection and due to shift in neutral axis in case of Unsymmetrical slender sections.

Limitations

Limitations are the similar to for BS5950-1:2000. See BS5950-1:2000 Limitations for more details.