The effect of time constants on the response of very large structures

Very large structures have long time-constants. These time-constants dictate how long the structure takes to respond to an action. When time-constants become large then the reponse of a structure to an action may be delayed. If subsequently, an anti-phase action occurs, then the structure may never reach the response expected. This paper reports on an investigation to evaluate the magnitude of the effect, using wind velocity data recorded from a large building in the field. In general terms it is found that reductions to the response of structures with long time constants can be predicted, and are likely to give a 20% advantage in structural design over the next few decades.