Rise to span — where it appears
Named by 2 essays across 2 fields — each of them below, with the objects they name alongside it.
The arch that leans instead of squashing
A masonry arch is asked whether a line of thrust fits inside it. A steel rib is asked a different question entirely: it is a column carrying an axial force along its whole length, and the mode it buckles in puts one half up and the other half down while the crown moves sideways.
A shell only if the grid takes shear
A curved surface carries load in its own plane at a fraction of the material a flat one needs, and every gridshell ever built is an attempt to buy that with members instead of with a surface. The attempt succeeds or fails on one property nobody draws — whether four bars meeting at a corner can resist being racked — and a pinned quadrilateral grid cannot resist it at all.
Named alongside it
The objects these essays reach for when they reach for this one.
BracingBucklingAntisymmetric modeArchCritical loadEffective lengthEigenvalueEquivalent continuumGeometric stiffnessGridshellInternal forcesLattice