Professional AS 4100:2020 Structure Analysis
Evaluate structural steel member capacities according to AS 4100:2020. This calculator automates section slenderness, member stability, and combined action interactions.
Design Check Overview
The calculator classifies your cross-section as Compact, Non-compact, or Slender based on plate width-to-thickness ratios and residual stress category. It then determines section capacities (tension, compression, bending, shear) and member stability accounting for effective lengths, buckling curves, and lateral-torsional buckling. Where multiple actions are present, combined interaction checks are performed automatically.
Clause Compliance Coverage:
- Tension Capacity (Sec 7): Evaluates gross section yield and net section fracture.
- Compression Capacity (Sec 6): Calculates φNc using the appropriate buckling curve (αb).
- Bending Capacity (Sec 5): Checks for lateral-torsional buckling (φMb) and local yielding.
- Shear Capacity (Sec 5.11): Web shear yielding and shear-moment interaction checks.
- Combined Actions (Sec 8): Cross-section and member stability for axial + biaxial bending.
Supported Section Types
I-Shapes - UB, UC, WB, WC
Channels - PFC
Tees - UBT, UCT
RHS / SHS
CHS
Angles - EA, UA
Current Limitations
- Net section area (An) uses gross area — bolt hole deductions are not applied to tension rupture checks.
- Single member analysis only — no automatic frame buckling analysis or system-level effects.
- No connection design, no composite construction (AS 2327), and no fatigue checks.
- Effective length factors (ke) must be user-specified (default 1.0). Moment modification factor (αm) is auto-calculated from the moment distribution.
- The calculator assumes the default section orientation shown in the preview. Major and minor axis inputs are relative to that orientation. Rotated or sideways mono-symmetric members, such as channels, tees, and angles, should be checked in the FEA workflow.
- Flexural-torsional buckling (Cl 6.3.3) is not performed as a separate compression member check. Only flexural buckling (φNc major/minor) is reported. Channels and angles in compression should verify FTB separately. A warning is issued for fabricated mono-symmetric I-sections.
- Torsion is not an input in the standalone calculator. In the FEA tool, torsion (Bredt-Batho) is checked for closed hollow sections (RHS/CHS) only — warping torsion for open sections is not performed.
Benchmarks: 58 independent test cases, 0.11% average difference
Full Documentation →