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Theoretical Research On Performance Of Steel Frame With Semi-Rigid Connection

Posted on:2020-10-26Degree:MasterType:Thesis
Country:ChinaCandidate:W LiuFull Text:PDF
GTID:2392330590957776Subject:Disaster Prevention
Abstract/Summary:PDF Full Text Request
In practical engineering,the stiffness of the connections between beams and columns could be between perfect rigid joints and hinge joints.The traditional design method of semirigid steel frame ignores the influence of semi-rigid connection at beam end and considers the connection between beam and column as hinge or ideal rigid connection.Previous studies on semi-rigid connected steel frames have focused on the properties of semi-rigid connections,while there have been few studies on the mechanical properties of the whole floors with semirigid connections.However,it is often necessary to evaluate the seismic performance of semirigid connected steel frames in many cases.In this paper,semi-rigid connection steel frame of interlayer resistance to lateral stiffness is deduced.In addition,since dampers are widely used in semi-rigidly connected steel frame structures,a formula for calculating the lateral stiffness of semi-rigidly connected steel frames with dampers is derived when considering the effect of dampers.Moreover,a direct design method based on performance is proposed.The main research contents of this paper are as follows:1)For the analysis of beam end semi-rigid connection with lateral resistance to lateral stiffness between the layers of steel frame structure,the influence of semi-rigid connection steel frame is deduced from the formula for calculation of resistance to lateral stiffness between the layers is derived using the formula of the steel framework layer between resistance to lateral stiffness.In addition,the empirical formula is used to calculate the steel framework ofhorizontal displacement and the basic natural vibration period of every layer.The calculation results are compared with those obtained by D-value method,so as to understand the influence of semi-rigid connection at the beam end on the horizontal displacement of steel frame structure under the action of horizontal force.2)In order to verify the validity of the formula for calculating the lateral stiffness of a steel frame with lateral displacement when considering the semi-rigid connection at the beam end,a series of finite element models of a steel frame with semi-rigid connection are designed with the number of spans,the number of floors,the stiffness of the semi-rigid connection and the load distribution as variables.First of all,the selection of appropriate semi-rigid steel frame model of the section size of beam and column,and then set up one-span &three-story,one-span &six-story,two-span &three-story and two-span &six-story semi-rigid steel frame finite element model.Taking the semi-rigid connection initial stiffness as variable,load of different distributions is applied on the semi-rigid steel frame finite element model.The inter-story displacement of a semi-rigid steel frame is calculated by using the derived formula of lateral stiffness.The calculated results are compared with those obtained by ETABS and the modified D value method to verify the validity of the deduced formula for calculating the lateral stiffness of the frame with lateral displacement.3)The calculation method of lateral stiffness of floors with damper steel frame considering semi-rigid connection is deduced,and then the horizontal displacement of each floor is calculated.At the same time,the calculation results are compared with those obtained by the modified D-value method and ETABS to verify the validity of the derived calculation formula,and laying a foundation for the further seismic performance evaluation and analysis of prefabricated structures.4)PUSHOVER analysis is carried out on the semi-rigid connected steel frame model with metal damper to study the seismic performance of the semi-rigid connected steel frame with joint damper.The PUSHOVER curve of semi-rigid connected steel frame model with metal dampers is obtained by using the simplified method proposed,which is then converted into a spectral acceleration-spectral displacement curve,and then the performance points of thesemi-rigid connected steel frame model with metal dampers are calculated.A seismic performance evaluation method for semi-rigid steel frame structures with metal dampers is also presented.5)A direct design method that can be applied to the structure of the damper layout is proposed,which is called the design method based on the seismic performance redundancy rate.The seismic performance redundancy parameters of the structure are deduced from several structural performance indexes,and the estimation formulas of the corresponding structural performance indexes are given.A design method of metal damper is presented,and the corresponding design flow is given.In addition,a Lever-Type Node Damper is designed and tested.
Keywords/Search Tags:Semi-rigid connection, Steel frame, Damper, Performance evaluation, Direct design method
PDF Full Text Request
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