| Controlling the lateral displacement of frame-core tube structure was one of the mainproblems under the action of horizontal loading. In order to reduce the lateraldisplacement, setting strengthened stories was a commonly used method. The positionand quantity of strengthened stories had a direct influence on the stress and deformationof the structure. For the study of strengthened stories effect on the seismic performanceof frame-core tube structure, this paper took a traffic building as the background, usinglarge-scale non-linear finite element software MSC.MARC to set up the differentstrengthened stories finite element models, and successively for each scheme model formodal analysis, seismic response analysis and static elastic-plastic analysis, the workdone and conclusions were as follows:(1)The influence strengthened story on the natural vibration of frame-core tubestructure was researched. Through comparative analysis of the first10order naturalvibration period from each structure scheme, it concluded the influence strengthenedstory on natural vibration period of frame-core tube structure. The results showed thatthe strengthened story could improve integral rigidity of the structure, reduce the naturalvibration period of structure, in which the impact of low order modal cycle was larger,high order modal cycle was not obvious.(2) The influence strengthened story on displacement and internal force response offrame-core tube structure was researched which was under the action of horizontalearthquake. Seismic response of the structure scheme was calculated by dynamictime-history analysis method, then the structure of the lateral displacement reaction andinternal force of frame column and core barrel were relatively analyzed. The resultsshowed that the strengthened story can effectively control the lateral deformation of thestructure under horizontal seismic action, while caused structural internal forcemutations and stress concentration at the same time. Along with the number ofstrengthened story increasing, internal force mutation extent and stress concentrationwere gradually moderated, the strengthened story could also reduce the flange of framecolumn’s shear lag phenomenon, improve the utilization rate of frame column.(3) The influence strengthened story on the seismic elastic-plastic performance offrame-core tube structure was researched. Through the analysis of the structurescheme’s plastic hinge development process under different lateral force models, it wasconcluded the influence regularity strengthened story on the order of plastic hinge, and then found the weak position of frame-core tube structure and seismic suggestions wereput forward. Comparing the power curve of each structure scheme, the results showedthat the strengthened story would raise base shear response of the structure, differentlateral force models had a greater impact on the power curve of structure, structuralseismic performance evaluation should be considered a variety of lateral force modelsanalysis results. |
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