| The high-rise flexible structure has become most popular in design and building currently,and it is the trend to construction and development of city in the future.It only considered horizontal ground motion for high-rise flexible structure in the traditional aseimic design,still it considered vertical ground motion sometimes.However,the research of many structure responses after earthquake showed that it generated tilt commonly for high-rise flexible structure under earthquake load.Thus,the influence of tilting ground motion to high-rise flexible structure can't be ignored due to the huge highness and small stiffness of high-rise flexible structure.The importance of tilting ground motion to high-rise flexible structure has attracted more and more researchers' focus,but the study has limited to singly considering the influence of tilting ground motion yet without coupling horizontal and vertical ground motion.Besides,it still has some defects needed to improve for the method of extracting tilting ground motion.Therefor this paper will put forward a new approach to tilting ground motion according to above point.And it will make research about the response of high-rise flexible structure under tilting ground motion and coupling horizontal tilting and vertical ground motion with finite element analysis and shaking table test.The specific research as follow:(1)according to the principle of frequency-rate method,the similarity of acceleration fourier spectrum between earthquake horizontal component and horizontal component under low-frequency range which means both of them has identical tendency.Moreover,change fourier to wavelet which has better time-frequency property and window function.Based on the principle of threshold deny noise,using software matlab to make program and extract earthquake tilting component from original northbridge earthquake recording.(2)Design a shaking table test,and guarantee the size of test model and related parameter according to the similarity of test parameter principle,then input the multi-dimensional earthquake including earthquake tilting component obtained by wavelet transfer method and get the results of model seimic response.The compare between each work condition result shows that the influence of earthquake tilting component on structure is relatively great.Based on dynamic principle and results of shaking table test,the dynamic equation of structure under coupling earthquake horizontal and tilting component has been derived.And build the model of shaking table test structure with finite element software ANSYS,then verify the accuracy of theoretical analysis through comparing the results between finite element analysis and shaking table test.(3)the high-rise flexible structural finite element model under the soil-structure interaction system will be carried on based on actual engineering condition,and set up the soil parameter in software ANSYS and simulate surface-surface connection with finite element.To decrease the amount of calculation,it will set up spring-damper system to simulate viscous-spring artificial boundary which can reduce volume of soil model.The equation of surface earthquake wave to bed rock earthquake wave will be derived based on theory of equivalent linear approximation of nonlinear stress-strain response and make corresponding inversion analysis on above Northridge earthquake wave to bed rock earthquake wave,then input them into finite element software ANSYS.There are four working conditions will be carried on including seimic horizontal effect,coupling seimic horizontal and tilting effect.Then make finite element calculation to gain the dynamic response of high-rise flexible structure under multi-dimensional seimic effect and the influence of tilting ground motion on high-rise flexible structural seimic response. |
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