Structural Engineering & Statics
where the load goes
Concept

Utilisation — where it appears

The ratio of a demand to the capacity at the same station, which for a member of varying section peaks where neither of the two is extreme.

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

30 kNwhat it can carrywhat it carriesworst at 3.00 mfree endroot79% used at the governing station · 70% at the root

The section that changes along the span

A prismatic beam is checked where the moment is largest, and everyone knows where that is. A tapered one is not, because the capacity is moving too — and for a cantilever with a load at its tip the governing station is exactly where the depth has doubled, with no length, no load and no material in the answer.

sections · tapered member 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.

Bending momentBracingConstruction sequenceDeflectionEffective lengthErection stabilityFully stressed designHaunchJoint stiffnessLateral restraintLateral torsional bucklingLoad path

All concepts