| Inter-column support is the core component of the longitudinal seismic resistance of industrial buildings.Double X-shaped angle steel inter-column braces is widely used in industrial buildings because of the same two-way stress and simple connection.However,due to the complexity of its response under rare earthquakes and And whether the ψ_c given according to the H-shaped steel braces test data are suitable for the double-plate X-shaped angle steel column bracings,there are still many problems worthy of further study.In this paper,the finite element analysis method is used to analyze the bearing capacity and seismic performance of double X-shaped angle steel column braces,and some meaningful conclusions are drawn:(1)According to the parameters such as angle steel spacing,lacing bar spacing,brace inclination angle and section form,95 double X-shaped angle steel inter-column support models are established according to the current codes in China.The static analysis of each support model is carried out by using finite element software ABAQUS,and the influence of each parameter on the static performance such as bearing capacity,stress distribution,failure mode and the like of the cross support is studied.It is found that the larger the distance between angle steel and lacing bar,the smaller the bearing capacity of cross brace.And with the reduction of the spacing,its influence on the bearing capacity decreases.If the spacing between two pieces of angle steel support is too large,the compression support will produce bending and torsional buckling Fermentation starter.(2)Through the research on the bearing capacity of bracing model,it is found that the design method of bracing between columns should be conservative according to the force of tie rod in the current code of our country.Based on the results of static analysis,this thesis introduces the strength participation coefficientζof compressed braces and gives a suggested calculation method of bearing capacity considering the interaction of braces with tension and compression,and compares the proposed formula with the calculation method in codes at home and abroad.The results show that the proposed formula is safe.(3)The influence of various parameters on the bearing capacity of cross bracing is studied through the analysis of the static performance of double X Angle steel columns.The results show that it is conservative to design inter-column braces according to the tension of tie rod.According to the static analysis results,this paper introduces the strength participation coefficient of compressive support and gives a suggested method to calculate the bearing capacity considering the joint action of tensile and compressive support,and compares the suggested formula with the calculation method in domestic and foreign codes.The results show that the suggested formula is partial to safety.(4)Based on the analysis of seismic behavior of double X-shaped column of angles,comparing the post-buckling bearing capacity of braces with their stable bearing capacity,the results show that the unloading coefficient ψ_c of compression bars in Chinese seismic code is on the high side,which generally underestimates the reduction of bearing capacity of braces under cyclic loading,and its consequence may underestimate the maximum seismic action of braces under tension.Based on the study of the post-buckling bearing capacity of braces,this thesis presents the recommended value of the unloading coefficient ψ_c of compression bars suitable for braces between double X-shaped column of angles,and the recommended formulas are compared with the domestic and foreign standard calculation methods.The results show that the method proposed in this thesis is safe. |
