Structure Dynamic Wind Load Identification And Response Anslysis For A Boiler Tower

Driven by the reformation of materials, the innovation of design philosophy and also the progress of construction technique, super high-rise buildings and some special structures are developed to be higher and more flexible. Under the action of typhoon, for such kind of buildings have lower natural frequencies which approach the main frequency band of the dynamic load, the wind-induced response get to be more intense. Therefore, wind vibration of such buildings has been aroused concern for a long while. The existent methods of research on wind effects on structures include measure on the spot, test in wind tunnel, numerical method and analyze in theory. This paper carries on the research mainly on the basis of wind-induced response measured on the spot and from the test in wind tunnel.Prototype test is the most reliable method to study on wind effects. With the structural dynamic response measured in prototype test under the state of typhoon, the structure dynamic characteristics and some other information about wind vibration can be analyzed,which provides a basis for the design of wind resistance of super high-rise buildings.But there still exits flaws in prototype test. The security risks, the huge cost, and the flaw that prototype test can be carried out only after construction or can only provide design foundation for the same type of structures.If prototype test is not possible, wind tunnel test gets to be widely adopted as the best-developed method. For now, wind tunnel test is necessary in order to get the parameters in the wind-resistant design for buildings with complex shape. And it can also be applied to study the wind pressure on complex architectural structures, and to summarize the law of wind load.Firstly, the methods of digital signal processing of the vibration response are introduced in this paper, which are used to recognize the dynamical characteristics of corresponding structure, such as natural frequency, damping and mode shape. And with these methods, the modal information of Hong Kong K11and a tonnage boiler was recognized, which was compared with finite element models, approving the reliability of above methods. Meanwhile, during the process of analyzing the response data from the high-frequency-force-balance wind tunnel test of the boiler, this paper found that intense wind induced vibration came out because of the non-high natural frequency of the model produced. Therefore, before analyzing, the component of inertia force should be eliminated from the data. Zhou Lianghao et al, deduced practical formulas to obtain the generalized force spectra of the first mode of the lattice towers, eliminating the resonance effects, based on the modification of wind load spectra of semi-rigid model by structure dynamic theory and random vibration theory. However, as the deduced formulas can be applied to calculate the generalized force spectra of the first mode only when the first mode is the type of translation or torsion, the effect, correcting the results of the above wind tunnel test, is imperfect. Therefore, this paper deduced the correction formulas With regard to the multi-mode wind vibration to eliminate the resonance effects. In the end, based on the revised response data, this paper analyzed the wind vibration and calculated the equivalent static wind loads.