Structural Engineering & Statics
where the load goes
Concept

Stiffness attracts load — where it appears

2 essays name this object, across 2 fields. What follows is each of them, and the objects they name alongside it.
simply supportedstatics alonesag 32.0propped at one endneeds stiffnesssag 18.0hog 32.0built in at both endsneeds stiffnesssag 10.7hog 21.3the load never changes; only what is holding the endsthe built-in case peaks at two-thirds of the simple span's moment

One support too many, and what it costs to know

Add a redundant restraint and the load has two routes to the ground. Equilibrium cannot say how it splits, and the answer turns out to depend on stiffness — which is a different kind of question.

deflection · indeterminacy P = 100 kNthe shallow beam takes 11.1 kN11% of it — one part of the stiffness in 9the deep beam takes 88.9 kN89% of it — 8 times the stiffness of its neighbourone load, two beams, one deflection: 5.0 mm each

The stiffest path takes the load

When two members share a force the split can be argued about. When they share a displacement it cannot — stiffness settles it, and nothing about the load or the plan drawing gets a vote. The consequence is that stiffening a lightly loaded member raises its stress, and the way to unload something is to soften it.

internal-forces · load sharing

Named alongside it

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

CompatibilityCrossing beamsIndeterminacyLoad pathLoad sharingMoment redistributionReaction distributionSection modulusSettlementStiffnessSupport settlementTributary area

All concepts