The Seismic Behavior Evaluation Of Frame Structure Based On Pushover Method

Compared with several methods of nonlinear static analysis, this thesis aims at the application of capacity spectrum method in frame structures, analysizes the influence of different lateral loads and compares its result with that of nonlinear history analysis. The nonlinear behaviors and performance indexes of structures under heavy earthquakes are also cheked in the thesis. Finally the capacity spectrum curve is used to simply estimate the damage of structures. Based on the Dongfeng Car Building in Wuhan City, a typical steel-frame structure, the article adopts the soft of ETABS to model and analyse. The primary content is as follows:First, the principles and application of three Pushover methods are introduced, especially the principle and application points of capacity spectrum method in ETABS in details.Second, modal parameters, obtained by modal analysis in ETABS, are compared with the measure data in the site. It proves the accuracy of the structure model. Modal analysis provides modal shape for Pushover analysis and dynamic history analysis. The mechanics and deformation of the structure is obtained by modal contribution response spectrum method, which is liable to appoint plastic hinges for the building.Then, different capacity spectrum curves are obtained by Pushover analysis under nine different load patterns. They are superposed with the reduced elastic-plastic spectrum to get the performance points, which testify the seismic capacity of the structure.Three different earthquake waves, EL Centro wave, Tangshan wave and an artifical wave at different acceleration levers are adopted to carry out the nonlinear history analysis. It gets the maximal bottom shears and top displacements, which form the capacity spectrum curves. Its results are compared with those of capacity spectrum methods, which proves the reliability of different load patterns.Finally, capacity spectrum curves are ultilized to estimate the damage status of structures, which simplify the identification of structures damage in some way.In this thesis, some significative suggestions are brought forward and they have certain reference value and project guidance meaning.The work of this thesis is to know the nonlinear behaviors of structure and offers some design basis for frame structures by nonlinear static analysis.