Non-Stationary Random Seismic Response Analysis Of Long-Span Spatial Structures Under Multi-Support And Multi-Dimensional Earthquake Excitation

The seismic spatial effect should be considered in the seismic response analysisfor the long-span spatial structures, because the support nodes move ununiformlyunder earthquake excitation. While the present seismic analysis methods in the "Codefor Seismic Design of Buildings" (GB50011-2001) are based on the hypothesis ofuniform excitation, so they do not suit for long-span spatial structures. So it isnecessary to study the seismic response methods for long-span spatial structuresconsidering seismic spatial effect. In this thesis, the seismic response analysismethods for long-span spatial structures under multi-support and multi-dimensionalnon-stationary earthquake excitations are studied. The main research work covers thefollowing aspects:(1) The pseudo excitation method is introduced to analyze the seismic responsefor long-span spatial structures. The random vibration approach for long-span spatialstructures under multi-support and multi-dimensional non-stationary earthquakeexcitation using pseudo excitation is studied.(2) The simulation approach for the stochastic earthquake ground motion modeland parameters and functions of the model are studied. Self-power spectrum density,mutual-power spectrum density, and time delay of the motion, mathematical model ofcoherence function between two excitations, coherence function betweenthree-dimensional earthquake suitable for the long-span spatial structures aresummarized.(3) Front-method is introduced while calculating the random response of largeDOF structures. By using his method, the requirement for the computer can bereduced and the calculating efficiency can be highly improved.(4) Computer program for the random vibration analysis has been developed. Andrandom vibration analysis is performed for Tianjin Olympic Status undermulti-support and multi-dimensional non-stational earthquake excitations.Comparisons are mode between multi-dimensional and single-dimensional response,uniform excitation and considering traveling-wave effect and incoherence effects,stationary response and non-stationary response.A conclusion is drawn that the seismic response of the long-span spatialstructures under multi-support and multi-dimensional non-stationary earthquakeexcitation is greatly different from that under consistent excitation. The detailedseismic analysis must be carried out in the design process of the long-span spatialstructures.