Strut and tie — where it appears
Named by 3 essays across 2 fields — each of them below, with the objects they name alongside it.
Plane sections stay plane, and what the assumption costs
Beam theory rests on one sentence about geometry. It is very nearly true for a slender member, wrong for a deep one, and everything in the subject that fails does so where it stops holding.
When there is no section to design
Beam theory needs a section, and a section needs the strain to be linear across it. Within about a depth of a support, a load, a corner or a hole it is not — and those are the regions structures actually fail in.
A check made on a perimeter, not on a section
Every shear check in this collection is made on a plane cut through a member. A slab sitting on a column has no such plane, because the shear leaves in every direction at once — so the check is made on a closed line, and a line grows with the column while the load grows with the square of the bay.
Named alongside it
The objects these essays reach for when they reach for this one.
Deep beamPlane sectionsSaint-Venant's principleAggregate interlockClamping forceColumn headControl perimeterDisturbed regionEffective depthEquilibriumFailure surfaceFlat slab