Kern — where it appears
Named by 3 essays across 3 fields — each of them below, with the objects they name alongside it.
Weight is the only thing resisting it
A structure that is strong enough everywhere can still be blown over, and nothing in its material properties has any part in whether it is. The whole answer is a weight and a width — and the failure begins long before anything tips, at the moment one edge stops pressing down.
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.
The middle third
A material that cannot be pulled imposes a condition on where the load may land, and the condition is a region rather than a point. For a rectangle it is the famous middle third; for every other section it is a shape nobody quotes, and one ordinary section's is nearly twice as generous as the rule allows.
Named alongside it
The objects these essays reach for when they reach for this one.
Bearing pressureEccentricityUpliftBending stressCrackingFactor of safetyFree bodyLoad balancingNo tension materialOverturningPrestressPrestress losses