Dynamic Time-history Analysis Of 3-Dimension Structures Under Wind With Non-classically Damping

Along with the development of the modern economy,scientific and technical progress, the city population concentration, the strain of ground-use, vehemence of the business competition and the development of radio broadcast, communication and the television, the application of the towering structure is also popular. So the hybrid structure of Steel Tower atop RC Building is just gradually extensively applied. This structure is elastically and dynamically investigated as the wind is applied on it in this text. The major contents are summarized as follows:(1) Non-classically damping structure will be seen as an aggregate composed of different substructures. Every substructure accords with Rayleigh damping assumer. The method of converted damping is a kind of approximate means,comparing to the way of material with different damping. There is certain difference between the both.(2) There are two way of the analysis of resisting wind which are Frequency-Region method and Time-Region method (direct integration algorithm and non-classical modal superposition). The towering structure was carried on analysis in Time-Region method in this text. Due to direct integration algorithm has precise result,the work in calculation is very heavy and the expenses is higher. Non-classical modal superposition cost lower. When the modal number superposed in internal force is twice more than that superposed in displacement, the result of internal force will be satisfied. Currently it is applied only at some important, special, complicated and high building of in the design,so this method will be realised by computer. Both the calculation accuracy and the calculation speed are greatly raised,so there will be dependable and valid practical value in the theories and actual engineering in the design.(3) The basic theory about wind and wind-induced vibration has been analyzed . The wind velocity measured by weather observation station in shanghai is switched to wind pressure changing with time by Bernoulli equation .Then the wind pressure is converted to wind load affecting 3D-Structure accord to criterion. Therefore, the wind load distributing in time and space is completed.(4) The dependability of common dynamic load module in DAS is validated. Afterward both the Steel Tower atop RC Frame and the Steel Tower atop RC Frame-shear Wall are elastically and dynamically analyzed in Time-Region and then displacement and internal force is compared in actual damping ratio,converted damping ratio and RC damping ratio. Direct integration algorithm and non-classical modal superposition are adopted and the excellence and disadvantage are compared as the analysis is going.