Response Control of a High-Rise Television Tower under Seismic Excitations by Friction Dampers

Abstract

High-rise television towers are prone to external wind and earthquake-induced oscillations in severe environments. To avoid excessive vibration under strong earthquakes, a large television tower requires certain measures to abate its dynamic responses. Friction dampers are simple and low-cost solutions for realizing the response control of television towers. In this study, response mitigation and performance assessment are conducted on a large-scale television tower with friction dampers under strong earthquakes. A 3D finite element static model of the high-rise television tower is first established, and then a 2D lumped mass dynamic model is developed. The mechanical model for the friction dampers is presented with the axial stiffness considered. The equations of motion of the damper–tower system under seismic excitations are then determined. The control force transformation, displacement increment transformation, and numerical integration of the coupled damper–tower system’s equations of motion are defined on the basis of the two aforementioned models. Finally, the seismic responses of a high-rise television tower system constructed in China are taken as an example to investigate the validity of the proposed control approach using the friction dampers. The results demonstrate that the implementation of friction dampers with optimal parameters in a large truss tower can substantially suppress the structural seismic responses in terms of peak responses and vibrant energy.