Structural Engineering & Statics
where the load goes
Concept

Load balancing — where it appears

Reading a draped tendon as an upward load rather than as a stress, so that prestressing becomes a matter of cancelling the load that is coming.

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

prestress alone-6.3320.61tensionat transfer-2.4716.76tensionin service7.613.82with no prestress12.67-12.67tension

The load put on backwards

Every other structure in this collection waits for its load and then resists it. A prestressed one is given a load first — chosen, permanent, and pointing the wrong way — so that when the real one arrives the two nearly cancel and the material never has to do the thing it is bad at.

internal-forces · prestress 05101520-600-400-200200400distance along the beam (m)bending moment (kNm)primarysecondarythe loadeverythingpushed down by 51.0 kN with nothing applied at all

The prestress that pushes back

On a simply supported beam a tendon is an internal matter and changes no reaction. Put the same beam on three supports and the tendon lifts it off the middle one, the support refuses, and the force it takes to hold the beam down is a reaction produced with no load applied at all.

internal-forces · secondary prestress

Named alongside it

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

PrestressSuperpositionBending stressConcordant profileContinuityCrackingEccentricityEquivalent loadIndeterminacyKernPressure linePrestress losses

All concepts