Structural Engineering & Statics
where the load goes
Concept

Built up column — where it appears

A column of two or more chords joined by a lattice, whose critical load is the harmonic sum of a flexural stiffness and the lattice's shear stiffness.

Named by 2 essays across 2 fields — each of them below, with the objects they name alongside it.

Also named here as euler load — the same set of essays touches all of them, so they are one junction rather than several.

the same, laid flatr = 4.3 mmλ = 9247 kNsquarer = 15.8 mmλ = 25397 kNtall rectangler = 57.7 mmλ = 691295 kNI-sectionr = 90.0 mmλ = 443146 kNthe dashed pair is ±r about the centroidthe bar is the Euler load at 4 m, to scale

The one length a section takes into a column

A section has an area, a second moment, two section moduli, a shear centre and a torsion constant. A column has heard of exactly one of them, and it is none of those — it is the length √(I/A), which is where the whole area would have to sit to give the section the stiffness it has.

sections · radius of gyration bending, as a solid column doesP_E = 1341 kNracking, which a solid column cannotS_v = 31500 kN1/P꜀ᵣ = 1/P_E + 1/S_v → 1287 kNthe smaller of the two governs, and here it is the bending

The column made of two columns

A solid column buckles when its bending stiffness runs out. A laced one has a second way to go — the lattice shears, the chords stay straight — and the two flexibilities add rather than the two stiffnesses. A battened column reaches 23% of its own Euler load and behaves as though its slenderness were twice what it is.

stability · built up column

Named alongside it

The objects these essays reach for when they reach for this one.

BucklingEuler loadRadius of gyrationAsymmetric sectionBattenBuilt up sectionChordEffective lengthEffective slendernessEngesserLacingMinor axis

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