Steel Angles: Principal Axes u–v and the Angle α
Why steel angles have rotated principal axes u–v, what tan α means, the invariant Iu+Iv=Iy+Iz, and why buckling and bending must use the principal axes.
Practical articles on European steel sections. Every table is generated from the same verified database that powers the profile pages.
8 min read
What HEB sections are, the h = b logic of the 100 to 1000 series, HEB versus HEA and HEM, why HEB dominates as a column, weights and dimensions of every size.
Read the articleWhy steel angles have rotated principal axes u–v, what tan α means, the invariant Iu+Iv=Iy+Iz, and why buckling and bending must use the principal axes.
CHS, SHS and RHS compared: torsion, bending, columns, connections and corrosion, plus a decision checklist for picking the right hollow section.
What EC3 cross-section classes 1–4 mean, how to classify with c/t and ε limits, and which resistance model (Wpl, Wel, effective section) each class uses.
EN 10210 vs EN 10219 hollow sections: corner radii, residual stresses, buckling curves, weldability and cost, and when to specify each.
What IPE beams are, the b≈h/2 logic of the 80–600 series, where they excel and fail, LTB and bracing, steel grades, and EN 10034 tolerances.
IPE, HEA, HEB or HEM? A practical guide to choosing European I-sections: strong-axis efficiency, columns, lateral-torsional buckling and connections.
How to map legacy ČSN and DIN steel profile designations (I, U, L, TR 4HR) to current EN families, and why old I means IPN, not IPE.
What i = √(I/A) really means, how slenderness and buckling curves a0–d work in EN 1993-1-1, and how to pick an efficient column section.
What Wel and Wpl mean, what the shape factor Wpl/Wel says about a cross-section, and which modulus Eurocode 3 lets you use for bending resistance.
Calculate the weight per metre of any steel profile with G = A × ρ, see why catalogue values differ slightly, and use quick tables for IPE, HEA and UPE.
St. Venant vs warping torsion, why closed sections beat open ones by orders of magnitude in It, and what Iw really does in lateral-torsional buckling.
How UPN and UPE channels differ, why the shear centre makes single channels twist, and when to detail them in back-to-back pairs.
5 articles in the order they build on each other: from what the designations mean to checking a column per Eurocode 3.