| With the prosperity of economy and science,the height of buildings is rising,and many super high-rise structures are springing up.As an important form among them,frame-core tube structure has been used worldwidely.However,the development of super high-rise buildings is also faced with huge challenges.The side effect of height is that structures are more vulnerable to earthquake and wind.As a result,it is necessary to promote the deeper exploration of super-tall structures.Furthermore,the research on RC frame-core tube super high-rise structure with top bare frame layer is relatively poor,so there is a large gap in the understanding of it.Based on an actual project,the performance of a RC frame-core tube structure with bare frame layer at the top is studied in this paper.The comprehensive analysis is carried out by means of digital simulation,model test and field measurement.The main research work and achievements are as follows:First of all,finite element analysis software PKPM was used to analyze the structure systematically.The influence of bare frame layer was also studied.Main conclusions can be summarized as below :(1)the basic status of the structure and the results of periodic analysis show that the structure has good anti-torsional abilities;(2)According to SATWE analysis,it is found that the shear weight ratio of some floors at the bottom does not meet the code limit,so the bottom of the structure needs to be further strengthened;(3)Pushover analysis of the structure shows that in terms of the law and distribution of plastic hinge,it basically meets the requirements of "strong column and weak beam",but the column hinge rate at the bottom is too high and needs further control;(4)The elastic-plastic time-history analysis of the structure shows that the column and wall are slightly damaged,which meets the design concept of "not falling down after a big earthquake".(5)The parameter analysis results of bare frame layer show that the number of bare frame layer has a greatest influence on the overall structure performance,especially the seismic deformation.But it increases the displacement of the top floor under the action of wind.According to Pushover analysis,the bare frame layer delays the time when the structure enters the plastic state,especially the middle part.(6)From the analysis of frame beam size in bare frame layer under wind load and frequent earthquake,the size change is almost useless on the overall structure.But under earthquake,it is beneficial to the overall structure.(7)From the analysis of the number and arrangement of frame beams in the bare frame layer,the arrangement has more influence on the overall performance of the bare frame layer compared with the change of the number,and the increase of the connecting beam between the outer frame and the core tube can improve the elastic-plastic deformation capacity of the overall structure and optimize the shear distribution of the structure.In addition,the wind tunnel test of the rigid model of the structure is carried out,and the wind-induced response of the structure is discussed and analyzed.Wind-induced response analysis and human comfort evaluation were carried out.Finally,the equivalent static wind load is studied,and the most unfavorable wind direction and the wind load value of each floor are obtained,which can be used to guide the optimization of structural design.Finally,the dynamic characteristics(frequency,damping and amplitude)tests are carried out on the spot,and the dynamic characteristics of the SAP2000 refined model are corrected.At the same time,through the measured data and the theoretical error analysis,the structural frequency calculation formula was obtained,which can well reflect the basic natural vibration period distribution law of the frame-core tube super high-rise structure with bare frame layer at the top and is in good agreement with the test value and numerical simulation results.The study aims to improve the safety,economy as well as rationality of structure,and provide more theoretical reference for the similar construction design optimization. |
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