So you need to Pick a problem: keep a skyscraper standing

Wind and earthquakes will both try to knock it over.

1. But wind peels off the sides in swirling vortices, one side, then the other, rocking the tower.
2. So you round or notch the corners and taper the tower, so the vortices fall out of step.
3. But it still bends.
4. So you add a stiff concrete core, tied to the outer columns by giant outrigger trusses.
5. But in a storm, the top still drifts.
6. So you hang a giant weight near the top. When the tower leans one way, it swings the other.
7. But then an earthquake shakes it from below.
8. So some towers sit on isolators, layers of rubber and steel that flex so the building moves far less.

A skyscraper doesn't survive by standing still. It survives by moving the right way.

Free illustrated book PDF, A4