The resonance conditions and application of passive and active control strategies in high-rise lifts to mitigate the effects of building sway

Tall buildings and high-rise structures are subjected to sway motions of large amplitude and low frequency due to the structural resonance conditions induced by wind loads and long-period seismic excitations. To mitigate the effects of resonance interactions on suspension and compensating ropes in a high-rise lift system the masses and geometry of the system can be adjusted to change the resonance frequencies to shift the resonance regions. However, in most cases the structural constraints and system design limitations do not leave much space for the possible changes to be effective. This paper revisits the system design parameters and how the simulation models and control strategies can be deployed to mitigate the effects of resonance conditions.