Elasto-plastic Models And Nonlinear Static Analysis Considering Higher Modes Influence

Nonlinear static procedure (NSP) has attracted the attention of more and more researchers for its merits of practicality. It has become one of checking computations tools for nonlinear distortion.Design procedure and analysis method of structure in earthquake are firstly introduced in this thesis. Then the basic theory, origin and the approach of the NSP was presented, including the selection of the lateral load, the determination of the target displacements and the evaluation of the seismic performance. The advantages and shortages of these methods were followed.It is one of important steps to select the suitable elasto-plastic model in the structural elasto-plastic analysis. The linear stiffness matrix of the plane column-beam element for a constantly increasing load is introduced to make the following contant understandable. Then the nonlinear stiffness matrix is derived including Clough's parallel model; Otani's series model and Li's series model. The refined plastic hinge model considering the geometric nonliearity was introduced too.As the developing of the economy, more and more super high-rises have been built. How to consider the impaction of the high mode has been the key point of the seismic analysis and design. This thesis summarizes the impactions of the high mode to the seismic design of the high-rise structure, introduces and improves the modal pushover analysis method. In this method, the consideration of the appropriate selects of reasonable numbers of modes and the adoption of the basic principles of the type modal decomposition method and the elastic-plastic response spectra considering strength reduce coefficient make the analysis results even near the actual performances of structures in big earthquake.This thesis has done two examples of the modal pushover analysis by the SAP2000.