Structural Engineering & Statics
where the load goes
Concept

Limit state — where it appears

3 essays name this object, across 2 fields. What follows is each of them, and the objects they name alongside it.
0.60.811.21.41.61.8200.511.5span, relative to the firstthey cross heredeflection runs out at 1.40strength runs out at 1.54the limitstrengthdeflection

Stiffness is not strength, and usually it is the one that governs

A beam can be nowhere near failure and still be unusable, because it has moved too far. For most long-span members that limit arrives first, and stronger steel does not help at all.

deflection · serviceability 00.020.040.060.080.10.120.1400.20.40.60.81sag at the middle of the baywater depth ÷ critical depthλ = 1.00, approached and never reachedreversed construction camber: δ₀ = 0.01

The water that will not run off

A flat roof deflects, the deflection makes room for water, the water deepens the deflection. It is the same equation as a buckling column, with rain in place of the axial load.

deflection · serviceability 00.511.522.533.544.55050100150200displacement, mmload, kNfriction 137 kNbearing 188 kNslipthe rising branch is drawn, not solved: it is elastic shear of the plates

The joint that carries nothing until it slips

Tighten the bolts hard enough and the plates are clamped together with a force nothing applied. The joint then carries shear by friction, the bolts are in tension and not in shear at all, and the load path has nothing in common with the joint it looks identical to.

connections · slip critical

Named alongside it

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

ServiceabilityDeflection limitSelf weightStiffnessAmplification factorBolt tensionConnectionCritical loadFrictionModulus of elasticityPondingPreload

All concepts