Structural Engineering & Statics
where the load goes
Concept

Lateral torsional buckling — where it appears

2 essays name this object, across one field. What follows is each of them, and the objects they name alongside it.
2000400060008000100001200002004006008001000distance between lateral restraintsthey cross at 3803the plastic capacity of the sectionelastic critical momentSt Venant torsion alone — what is left at long lengthswarping dominates here

The beam that fails sideways

A deep narrow beam bending in its strong plane can, at a moment well below its capacity, swing out of that plane and twist. The failure has nothing to do with how much it can carry and everything to do with what is holding it.

stability · lateral torsional 02040608000.20.40.60.811.21.41.6brace stiffness (units of EI/L³)effective length factor k23.2 EI/L³ = 1.41 N꜀ᵣ/L0.77 — held1.32 — freepast the threshold the frame buckles in a mode the brace does not hold

The most dangerous day is before it is finished

A structure is analysed once, complete, with every restraint present. It spends weeks in states nobody drew — a beam landed with no deck on it holds 17% of the moment its section is worth, a frame not yet braced buckles at a third of the load it will, and a bolt not yet tightened is a pin where the analysis assumed a fixity.

stability · erection stability

Named alongside it

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

Effective lengthLateral restraintBracingCompression flangeConstruction sequenceCritical momentErection stabilityJoint stiffnessLoad pathMoment diagramOverturningRobustness

All concepts