Damage Evolution Analysis And Experimental Research On High-rise Steel Frame Structure Due To Strong Earthquakes

In this paper, the damage evolution criteria and seismic behavior of high-rise steel structure were researched from the aspects of damage model, seismic vulnerability analysis, shaking table test and collapse resistance design, the main work are as follows:(1) An improved two-parameter damage model was proposed by considering the effect of hysteretic deformation amplitude to accumulative damage energy dissipation based on the analysis of existing two-parameter earthquake damage models, and the damage model was applicable to steel structures. A damage analysis to a9-story steel frame structure model was conducted under unidirectional and bidirectional seismic actions, the damage evolution time history curves of the structural weak story under different intensity of earthquake motions were obtained, and the corresponding damage states were defined, then the feasibility of the damage model was verified;(2) A series of shaking table tests on a1:4scaled3-story steel and concrete hybrid structure were carried out, the structural dynamic characteristics, dynamic response and damage evolution criteria of the steel frame structure under the strong earthquakes were researched and analyzed. The damage evolution time history curves of the steel column at the top story under different intensity of earthquake motions were obtained using the proposed damage model. The structural failure mechanism and the collapse damage criteria were researched through the IDA results of structure and the variation of the displacement time history curves of top story column under three earthquake inputs;(3) A seismic vulnerability analysis to the9-story steel frame structure model was made using the proposed damage model, the exceeding probability of the structure reaching different damage states under the given earthquake intensity were obtained, and the assessment of damage status and seismic behavior to the steel frame structure was conducted through theoretical vulnerability curves;(4) According to the response characteristics of the steel frame model structure under strong earthquakes, an optimization design was made to the weak stories. The comparative analysis of vulnerability for the original structure and the one after optimization design under different earthquakes was made, and the resistance capability to collapse for the original structure and the one after optimization design was analysed based on Collapse Margin Ratio (CMR). The results indicated that the safety and reliability of the optimized structure under the same intensity earthquake were obviously improved.