5. Movers and shakers

What do a jumbo jet, a cruise ship, a long span bridge, and a tall skyscraper have in common? They are, in essence, gigantic tubes or boxes that act as beams. ‘Movers and shakers’ examines the commonalities and differences between these four types of large, impressive, moving structures to reveal much about their main functions, the forces they must resist, and the ways in which they have to be strong. It shows that structures can be in dynamic equilibrium, i.e. connected structural parts moving as one whole structure. But two extra internal forces—inertia and damping—must be considered. There are also several complex forms of instability including buckling, resonance and flutter.