Mechanics Properties Of Double-Limb-Double-Plate Connections On Steel Pipe And Angle Steel

For the main material for steel pipe,oblique-angle steel tower structure,the main material-inclined material connection joints often adopt the tube-single limb single board connection.Because the angle steel in the pipe-single limb connection joint is in the eccentric force state,the joint plate is subjected to a larger bending stress while bearing the plane tensile and compressive stress,and the weld joint strength between the main material and the joint plate is very unfavorable.In order to avoid the bending stress of the nodal plate and angle steel as far as possible,in this paper,a new type of connection node is proposed,which is a two-plate connecting joint of pipe-double limb,and the mechanical properties of two-limb double plate joints are deeply researched by means of theoretical analysis,numerical calculation and experimental research,and the results show that under the same load,The maximum stress of the pipe-double-plate connection joint is much smaller than that of the single-limb one-board node.In order to achieve this goal,the main research contents and results are as follows:(1)This paper introduces the mechanism of force transfer of single-limb joint the failure mode of connection between steel pipe and joint plate is given,and the calculation method of strength and stability of angle steel under eccentric tension and compression is given,which provides a theoretical basis for studying the mechanical properties of two-plate joints.(2)For the first time,the pipe-double limb double plate connection node is proposed,in this paper,the mechanical properties of the pipe-double-limb double plate and the single-limb connection joint are analyzed,and the results show that the section stress of the steel tube-single limb connection joint with the eccentric load is the angle steel in the axial pull,2.5 times the stress of the section under pressure,the end stress ratio of the joint plate-plate joint is at least 4 times higher than that of the pipe-single limb plate node.The mechanism of force transfer of Bolt Group connection is studied,and the results show that the force of the bolt passing through the bolt group is much larger than that of the middle position.The theoretical basis is provided for the reasonable arrangement of the joint of the pipe-double-plate connecting bolt.(3)The static load test of the pipe-single limb single plate node and the two-limb double plate joint is carried out.The test results show that the bearing capacity of the two-plate joint is higher than that of the pipe-single limb,and the finite element analysis is carried out,the results of the test and the finite element result are coincident to further verify the reliability of the two-plate joint.(4)The fatigue test of pipe-single limb single plate node and pipe-double limb double plate joint is carried out.The weak links under the fatigue load are found out,and the test data support is provided for the further optimization of the tubular-double double plate node structure.The fatigue strength finite element analysis of the corresponding node is carried out,the numerical results agree well with the experimental results.On the basis of further improvement,the preliminary results of this paper can be applied to the engineering practice of connecting steel pipe main material and angle steel oblique material node.