Research On Seismic Performance Of Prefabricated Structures With Weak Frame-light Steel Composite Walls

To provoke the development of cold-formed thin-walled steel structure applied in highrised buildings,Prof.Tianhua Zhou added the concept of “ring beam-structural column” to the cold-formed thin-walled steel structure system,then proposed an advanced version,namely the prefabricated structures with weak frame-light steel composite walls system.This structural system has better lateral stiffness and bearing capacity,and a wider safety margin.It does not require manual installing and welding.Comparing to the traditional steel structure,it can be manually assembled without a crane,which makes the fully assembled construction possible and makes the assembly process greener.Besides,the cold-formed thin-walled steel structure has a lighter weight,which can improve construction efficiency and shorten the construction period.Based on the prefabricated structures with weak frame-light steel composite walls system,this thesis analyzed the seismic performance of the prefabricated structures with weak frame-light steel composite walls system in SAP2000,and conducted a series of variable parameter analysis of the structure.The main research contents of this paper can be summarized as follows:1.Firstly,the research background and significance were described briefly,and the advantages of prefabricated structures with weak frame-light steel composite walls was illuminated and summarized.In addition,the technical scheme of adding prefabricated structures with weak frame-light steel composite walls in this paper was elaborated.ABAQUS software was applied to calculate the equivalent rotational stiffness of this joints of the ring beam-thin layer square concrete-filled steel tube column,in order to observe the stress distribution of the joints when they rotate and discover the weak parts of the joints,which would benefit the following working process.2.The seismic performance of prefabricated structures with weak frame-light steel composite walls was illuminated through the SAP2000 finite element software.The main dynamic characteristics of the model structure under 7-degree frequent earthquake conditions were analyzed through the vibration mode decomposition response spectrum method: natural vibration period,vibration mode,and the maximum displacement angle,maximum displacement,maximum displacement ratio,shear weight ratio,and stiffness weight ratio of the structure were calculated,in order to analyze the seismic performance of the structure.3.The time-history analysis method was applied to analyze the interlayer displacement angle,maximum displacement ratio,maximum displacement,and base sheer force of the prefabricated structures with weak frame-light steel composite walls under two different levels of earthquake action,namely,a 7-degree frequent earthquake and a 7-degree rare earthquake.Then the data obtained from response spectrum analysis were analyzed to study the changing characteristics of this model under earthquake,so as to find out the seismic performance of this structure.4.Based on the seismic performance analysis results of the prefabricated structure with weak frame-light steel composite wall studied in this paper,the key parameters,including wall thickness of the thin-wall concrete-filled steel tube column,the wall thickness of the steel beam and the rotational stiffness of the beam-column joint,of the structure were selected.Three models were established for each parameter respectively,based on which modal analysis and time-history analysis were carried out,and the relevant parameters(e.g.,inter-storey displacement angle,maximum displacement,base shear and maximum acceleration)were compared and analyzed.Analyze the seismic performance differences between the structural node and the hinge joint and rigid joint schemes of beam column nodes under the rotational stiffness obtained in Chapter 2.The seismic performance changes of the prefabricated structures with weak frame-light steel composite walls system(under different thicknesses of the thinwalled square steel tube columns and different thicknesses of ring beams)were obtained to choose the optimization plan.