Lateral system — where it appears
Also named here as shear wall — the same set of essays touches all of them, so they are one junction rather than several.
How a tall building stands still
A shear wall bends and a framed tube shears, and the two deflected shapes are the wrong way up for each other. Tie them together at every floor and the pair is stiffer than the sum of their stiffnesses — because near the base the wall holds the frame back and near the top the frame holds the wall.
The corner that moves most
A lateral force is shared out in proportion to stiffness only if it passes through the centre of rigidity, which is not the centre of the plan and not the centre of mass. The distance between the two is a torque, and the wall that pays for it is the one furthest away and carrying least.
The floor is a beam lying down
A floor plate spans horizontally between the walls that resist a lateral load, carries a distributed inertia load, and has chords, a web and a span-to-depth ratio like any other beam. Its stiffness decides whether the walls share the load by their stiffness or by the area of floor nearest them — and the familiar tributary answer turns out to be neither limit.
Named alongside it
The objects these essays reach for when they reach for this one.
Shear wallAccidental eccentricityCentre of rigidityDiaphragmLoad sharingPlan torsionStorey driftChord forceCollectorDeep beamEccentricityErection stability