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The Research On The Mechanical Performance Of The Steel Frame-concrete Core-tube With Semi-rigid Connection

Posted on:2013-07-04Degree:MasterType:Thesis
Country:ChinaCandidate:X LiFull Text:PDF
GTID:2232330374990879Subject:Structural engineering
Abstract/Summary:PDF Full Text Request
The tall building hybrid structures, which are composed with steel frame andconcrete core-tube, have been most commonly used in our country recent years.However, analysis of the structures is based on the assumption that the connectionbetween beams and columns is totally rigid. This does not square with the fact that theconnection between beams and columns is semi-rigid in the practical engineering. Butso far, the systematical researchs that directly against the structures considering theaffect of the semi-rigid connection are inadequate. In view of the above-mentionedsituations, some scholars’ research achievements and the stipulations in codes aboutthe performance of semi-rigid connections and structures at home and abroad havebeen summarized, and the steel-frame-concrete core-tube structures with extendedend-plate semi-rigid connections have been researched in this thesis in older to obtainthe static and dynamic performance of the structures. The main contents are as follow:1. Based on the linear model of the M-θ_r curve and infinitesimal deformationtheory, the theory of the hybrid structures with semi-rigid connection have beenanalysed in this thesis. The stiffness matrix of the semi-rigid beam element has beendeduced with the introduction of the constraint factor r. And the influence mechanismof the semi-rigid connection to the hybrid structures has also been put forword. Then,the characteristic value of stiffness of the semi-rigid structures has been revealed.Subsequently, several extended end-plate connections have been analyzed through theABAQUS program in order to gain the M-θ_r curve and verify the correctness of theformula about the connection’ initial stiffness R_k in literature [5].2. The initial stiffness R_k and the constraint factor r of the extended end-plateconnections whose conformations satisfy the demands of the CESC260:2009havebeen calculated through the formula in literature [5]. Then,23groups of R_k and r havebeen set as connection stiffness conditions. And then30-story steel frame-concretecore-tube structures with different connection stiffness conditions have beenestablished by the SAP2000program. Finally, the wind load upon the structures havebeen analysed by static method, earthpuake upon the structures have been analysed bythe response spectrum method and dynamic time history method.3. By analyses from above-mentioned, essential quantities of the structures suchas the stiffness characteristic, the vibration periods and the sidesway, the interstory ratio, the internal force of the entire structures, the internal force of the concretecore-tube, the internal force of the steel frame under the wind and the earthquake andthe displacement and internal force historys and envelopes under the EL-CENTROhave been obtained in the thesis. And then, the laws of the static and dynamicperformance of the structure have been brought to light by analyzing theabove-mentioned quantities qualitatively.4. Finally, some key quantities and their variable factors such as the formertwo-class vibration periods and the sidesway of the top level, the maximum interstoryratio, the maximum internal force of the entire structure, the maximum internal forceof the concrete core-tube, the maximum internal force of the steel frame of thestructures with different stiffness conditions under the wind and the earthquake havebeen analysed quantitatively. Then, series of fitting formulas between theabove-mentioned quantities and R_k, r have been brought to light, and the influencesof the semi-rigid connection upon the structures under different horizontal loads havebeen compared and analyzed based on the fitting formulas above. At last, the rigiditydiscrimination criterion between beams and columns of the structures have been putforword.
Keywords/Search Tags:Steel-frame-concrete core-tube, Semi-rigid connection, M-θ_r curve, Initial stiffness, Constraint factor, Quantitative analysis, Variable factors
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