Study Of Wind Vibration Control For A Large Cantilevered Steel Spatial Truss With Circular Tube Viscoelastic Dampers

This dissertation describes the studies of the dynamic behaviors, the aging behaviors and the fatigue behaviors for the circular tube viscoelastic dampers. Based on these, the theory studies and design of the wind vibration control for a large cantilevered steel spatial truss with circular tube viscoelastic dampers of the roof engineering at Hefei Olympic Center is finished and this building engineering has been set up and got a good social benefit and economic benefit..The VE material has the damping character that the strain is delayed to the stress, so the VE damper and the energy dissipation braces are basically velocity dependent device of reducing vibration which can be used in seismic structure and wind resistant structure. The dynamic properties of the circular tube VE dampers are tested under different environment temperature, excitation frequencies and shear strain amplitudes. The test results show that the circular tube VE dampers have stable properties and excellent capacity for energy dissipation,which can be used in the vibration control of engineering structure under earthquake or wind loads. The dynamic property tests of the aged circular tube VE dampers are also introduced in this dissertation, and the conclusion is drawn that the circular tube VE damper has good aging property. Meanwhile, the fatigue test of the circular tube VE dampers is performed. The test results indicate that the circular tube VE dampers have good fatigue properties under earthquake action or wind load. It was noted that the earthquake action is different from the wind load. The earthquake action has strong intensity and short duration, but the intensity of wind loading is weaker than that of earthquake action and its duration is longer. When VE dampers are applied to the wind-induced vibration control of buildings, the number of loading cycles must be taken into account in the design. Based on the test results, the effect of the number of hysteretic loops on the mechanical properties of the circular tube VE damper is studied in this dissertation.In this dissertation, the wind-induced vibration control theory and design principle for large cantilevered steel spatial truss are fully studied. Such as modal strain energy method is modified, and the reasonable arrangement of VE dampers, the calculation formula of vertical control force for energy dissipation brace, the design method of circular tube VE damper, the equivalent stiffness and the equivalent stiffness loss factor are introduced.At last it is involved in that the circular tube VE dampers are applied to the large cantilevered steel spatial truss at Hefei Olympic Sports Center to reduce the wind-induced dynamic response. The analytic results show that the vertical displacements of the 28.23m cantilevered steel spatial truss roof are obviously reduced after installing the circular tube VE dampers.