Structural Engineering & Statics
where the load goes
Concept

Idealisation

3 essays name this object, across 2 fields. What follows is each of them, and the objects they name alongside it.
1289.510.5ΣM about one support gives the other reaction; ΣF then gives the first

Everything adds to nothing, and that is the whole of statics

A structure that stays put obeys two statements — the forces on it sum to zero, and so do the moments. Every number in the subject comes out of those two sentences.

equilibrium · equilibrium resultant 24.0at x = 5.33, the centroid of the areamomentspread: 24.6replaced: 42.7reactions agree exactly (8.00 and 8.00); the peak moment does not

The load that is spread out, and the force that replaces it

A distributed load can be swapped for a single force at its centroid. The reactions come out identical and the bending moment does not, and knowing which side of the cut the swap is legitimate on is most of the skill.

equilibrium · distributed load worst secondary bending: 24.3% of the axial stress, in the member markedaxial force there 16.7 kN · end moment 0.20 kNm · slenderness of the member 18the same members, the same loads, the same solver — only the releases differ

The joint that is not a pin

Every truss on this site is analysed as though its joints were frictionless pins. Almost none are. The bending that follows is called secondary, which is a claim about size — and the claim is checkable.

structures · truss

Named alongside it

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

Free body diagramCentroidDistributed loadForce equilibriumJoint rigidityLoad pathMethod of jointsMoment connectionMoment equilibriumReactionsResultantRigid body

All concepts