Optimal Vibration Control Design of Antenna Mast on Super High-Rising Structures Against Multi-Hazards of Earthquake and Wind

Abstract

Antenna mast structures are usually set on top of modern super high-rising structures to meet the requirements of communication and aesthetics, and such buildings are highly sensitive to horizontal loads that can greatly increase the acceleration and displacement responses during their life-cycles owing to the inherent high flexibility and low damping. As a result, the antenna masts with small mass and stiffness may suffer serious whiplash effect under the earthquake or wind excitations. In this paper, a multi-hazard protective system with hybrid isolated and energy-dissipated devices of isolation bearing, viscous damper and mild steel damper is presented for the typical inserted antenna mast structures on super high-rising structures. To determine the optimum parameters of the hybrid system that maximize the structural control efficiency under a single hazard of earthquake or wind load, as well as the coupled conditions of these two hazards, an optimization method based on the genetic algorithm is developed for the presented hybrid control system to resist various hazard scenarios. Objective functions are further proposed to penalize the accelerations and relative displacements at the top of the antenna mast structure. Taking a super-tall TV tower as an example, the OpenSeesPy platform is employed to establish the finite element (FE) model. The numerical results show that the optimization scheme for the hybrid energy-dissipated antenna mast system under a single hazard is not suitable for the other hazard condition, while the optimized results for the multi-hazard condition can give consideration to the effects of both earthquake and wind. Moreover, the sensitive analysis is performed to investigate the effects of each parameter of the hybrid system on the objective functions. It can be concluded that the proposed hybrid system performs well under earthquake, wind and coupled multi-hazards, which is of practical significance for the vibration control of antenna masts on super high-rising structures.