Do Tall Buildings Really Move?

Herschel2012-01 225x300The structure of a tall building ensures that it deflects under any loading and wind is no exception. The wind will travel around a tall building in such a way that it experiences loading that is both static and dynamic. The latter loading can be sympathetic to the eddies in the wind near the building, that are a similar size to the building itself, and so move it in such a way that the occupants may be able sense the motion. As humans we sense the accelerations rather than displacement or velocity. For example, in a lift or elevator one notices the initial acceleration and final deceleration, but not the intervening velocity or displacement. The same is so for the horizontal motion in a tall building. The displacements may be quite large in a very tall building, but it is the accelerations that one feels. Your wind engineer will work with the structural engineer to obtain the needed amount of mass, stiffness, and damping to make the upper-level building motions imperceptible.