Structural Engineering & Statics
where the load goes
Concept

Optimisation — where it appears

Choosing a structure's proportions so that two competing limits arrive together, which is where the best member of a family usually sits.

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

00.050.10.150.20.250.30.3501020304050overhang, as a fraction of the spanbest at 21% — peak 8.8sagging, mid-spanhogging, over the supportmoving the supports in by a third of the way halves the worst moment

Where to put the supports, which is not at the ends

Moving the supports of a uniformly loaded beam inward by about a fifth of its length halves the worst bending moment. The load has not changed and nor has the beam.

internal-forces · support layout flat: I = 6750 mm⁴folded: I = 67.50×10⁶ mm⁴300gain 10000× = (100)²limited by buckling of the leg: the leg goes at 27 N/mm²

Folded until it spans

A flat sheet has a second moment of area of B·t³/12 and will not span anything. Folded, the same material has B·t·h²/12, and the gain is exactly the fold depth over the thickness, squared — a ratio with no material in it and no width in it.

structures · folded plate

Named alongside it

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

ContinuityEfficiencyForm findingHogging and saggingLocal bucklingMoment envelopeOne way spanningOverhangPlate bucklingPlate slendernessPoint of contraflexureReactions

All concepts