About this Application
This tool performs Ultimate Limit State (ULS) cross-section and member stability checks
for steel I/H sections (IPE, HEA, HEB, HEM) according to EN 1993-1-1 (EC3).
It evaluates 22 independent checks: tension & compression capacity (§6.2.3–4),
uniaxial and biaxial bending with shear interaction (§6.2.5–10), flexural and torsional buckling
(§6.3.1), lateral-torsional buckling with moment gradient correction (§6.3.2), and combined
compression + bending interaction via both Annex A (Method 1) and
Annex B (Method 2) (§6.3.3).
Multiple load combinations can be entered in the table below.
Use Run Design Checks to evaluate the selected profile, or
Optimize Section to automatically find the lightest passing section across all
IPE → HEA → HEB → HEM series.
Input Parameters
Cross-Section
Material
Buckling Lengths
LTB & Interaction
Selected Section Properties
Load Combinations N: negative=compression, positive=tension | M, V sign convention per EC3
Click to select · Double-click to edit · Right-click for row operations & CSV export.
Detailed Results -; Combination:
| # | Check (EC3 Reference) | U.F. | Status |
|---|
Overall Summary (Governing Utilisation Factor per Combination)
All Combinations (Utilization Factor Summary)
‐ Green = OK (UF ≤ 1.0) | Red = Fail (UF > 1.0)
Design Notes and References
Cross-section checks (sec.6.2)
- [1] Tension §6.2.3: NEd/Npl,Rd (NEd>0 only)
- [2] Compression §6.2.4: NEd/Nc,Rd (NEd<0 only)
- [3] Bending My §6.2.5: My/Mc,y,Rd, Mc,y,Rd=Wpl,y·fy/gM0
- [4] Bending Mz §6.2.5: Mz/Mc,z,Rd
- [5] Shear Vz §6.2.6: Vz/Vc,z,Rd, Vc,z,Rd=Av,z·(fy/√3)/gM0
- [6] Shear Vy §6.2.6: Vy/Vc,y,Rd
- [7] My+Vz §6.2.8: My/Mcy,V,Rd; if Vz>0.5Vpl,z: ρ=(2V/Vpl-1)², Wpl,y,red=Wpl,y-ρ·hw²·tw/4
- [8] Mz+Vy §6.2.8: Mz/Mcz,V,Rd
- [9] N+My §6.2.9: My/MN,y,Rd; reduced if NEd>min(0.25Npl,0.5·hw·tw·fy/gM0)
- [10] N+Mz §6.2.9: Mz/MN,z,Rd; reduced if NEd>hw·tw·fy/gM0
- [11] N+My+Mz §6.2.9: biaxial (My/MN,y)²+(Mz/MN,z)² ≤ 1 (α=β=2 for Class 1/2 I-sections)
- [12] N+My+Vz §6.2.10: as [9] but with shear-reduced Wpl,y
- [13] N+Mz+Vy §6.2.10: as [10] but with shear-reduced Wpl,z
- [14] N+My+Mz+V §6.2.10: biaxial with shear-reduced Wpl
Member stability checks (sec.6.3)
- [15] FB y-y §6.3.1: NEd/Nb,y,Rd; χy from buckling curve (Table 6.2)
- [16] FB z-z §6.3.1: NEd/Nb,z,Rd
- [17] Torsional/TF buckling §6.3.1.4: Ncr,T=(1/i₀²)·(G·IT+π²·E·IW/Lcr,T²); uses z-z buckling curve
- [18] LTB §6.3.2: My/Mb,Rd; Mcr with C1; curve b (h/b≤2) or c; kc-modification per Table 6.6
- [19] Interaction Eq.1 Annex A (Method 1): kyy,kyz from Table A.1; Cmy/Cmz from ψy/ψz via Cmy,0 formula
- [20] Interaction Eq.2 Annex A (Method 1)
- [21] Interaction Eq.1 Annex B (Method 2): kyy,kyz per Table B.2 (susceptible to LTB); CmLT=max(0.4,0.6+0.4ψy)
- [22] Interaction Eq.2 Annex B (Method 2)
E = 210 000 MPa, G = 80 769 MPa. Class 1/2 assumed. Interaction checks only active for compression (NEd<0). Annex A Cyy/Cyz/Czy/Czz set to 1.0 (slightly conservative, typical for I-sections).