Structural Engineering & Statics
where the load goes
Concept

Partial interaction — where it appears

The state of a composite member whose two parts are joined by a connection of finite stiffness, so that they slip relative to one another. Half of the available composite benefit arrives for a small fraction of the full connection, which is why studs at a wide spacing behave nearly as though the parts were glued.

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

051015202530354000.20.40.60.81αLdegree of interaction96% at αL = 15.8one beamtwo beamsEI∞/EI₀ = 3.24 · the whole range is a factor of 3.24 in deflection

Half the studs, and most of the beam

Bonding two layers together quadruples the stiffness of the pair. A real connection is a row of studs that deform, so the layers slide a little and the beam sits between the two answers — but not halfway between, and the number that decides where is a single dimensionless group.

internal-forces · partial interaction 146 MPaunpropped24.6 mm at midspansteel alonecomposite93 MPapropped14.3 mm at midspancomposite

The section that changed while it was being loaded

A stress is computed from a moment and a section modulus. When part of the moment arrived while the section was a different shape, there is no single section modulus to divide by — the stresses add and the properties do not, and two identical finished beams can differ by half again in stress with nothing on the drawing to say which is which.

sections · staged section

Named alongside it

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

Composite actionCamberCompatibilityConstruction sequenceCreepDeflectionDifferential shorteningDuctilityEquilibriumInterfaceLocked in stressModular ratio

All concepts