The Elastoplastic Time History Analysis Of Complex Steel Structure With Taking The Shangri-la Theatre As Example

Because of the advantages of light weight,simple manufacturing,excellent plasticity and toughness,as well as short construction period,the steel structure has been widely used in China in recent years,especially in public buildings with high security requirements,such as large span structures,tall and slender structures.With the increasing height and appearance of these buildings,the elastic analysis method is reaching its limitation hence the elastic-plastic seismic performance analysis as fine design theory is becoming more and more important.In this paper,the research object,which is based on the 7 degree(0.15g)seismic fortification area,is a public building with floor of large openings,conversion of vertical components,and irregular torsion,planes and verticals.This unique and complex structure makes its seismic performance research based on elastic-plastic analysis of ABAQUS be of theoretical and engineering practical significance.The main contents of this paper are as follows:(1)The research and application of elastic-plastic analysis method at home and abroad are briefly reviewed.The basic theory,the earthquake wave course selection,the convergence control criterion and other relevant parameters in the two nonlinear dynamic elastic-plastic analysis related to this paper are discussed.The model is established with the help of interface software and manual programming.(2)Based on the architectural background of Shangri-La Theater,the ABAQUS finite element software is used for the dynamic elastic-plasticity analysis.According to the suggestion of "General Code for Design of Seismic Behavior of Construction Engineering",two strong earthquake acceleration time courses and one artificial earthquake acceleration time course are selected and applied to the structure for the modal analysis and elastic-plastic dynamic time history analysis.Based on the principle of envelope,the lager earthquake wave effect is used to study and analyze the elastic-plastic story drift angle and plastic strain development of the structure,and especially track the structural traits of the key components such as transfer columns and beams,etc in this project in the whole process.(3)With the help of ABAQUS post-processing program and EXCEL,the massive data produced by the above researches are identified,extracted and integrated.Suggestions are given for the design of the structure according to the results of the elastic-plastic analysis.The results show that:(1)In contrast to the results of ABAQUS analysis,although there are result differences,the traditional elastic time history analysis and MIDAS-gen elastic-plastic analysis method can ensure the seismic safety of the structure as a whole.(2)The elastic-plastic time history analysis results show that,although the maximum drift displacement angle is 1/61,the distribution of plastic strain indicates a gentle plastic strain of the structure and component materials in the whole case,which mostly reach the yield stage of plastic steel but note enter the hardening stage yet.Many components under the large earthquake have high security reserves.(3)The components of the project are slightly elastic-plastic,but it is unfavorable that the positions of the base of the frame column,the beam column connections and their shadows have the maximum plastic strain.Therefore,these areas should be further strengthened in the pursuit of higher security objectives.(4)For the vertical irregular structures with vertical stiffness reduction,the seismic acceleration amplification factor of the tower top should be 5.0(larger than the result of traditional analysis method).Although the structural shear force obtained by the traditional analytical method(CQC)is partial safety,the seismic effect of the upper floor layer obtained by the time history analysis is larger than that obtained by the CQC method for this project.