| With the construction of super high-rise buildings and the improvement of seismic performance standards,various semi-rigid steel beam-to-column joints have been widely used in various projects.The relevant specifications for beam-to-column end-plate joints have been adopted in Europe at first,but there are many kinds of semi-rigid joints.There are different stress forms and analysis methods for different joints,so there is no universal method to study them.In addition,GB50017-2017,which has just been published in China,simply stipulates the end-plate connections of beams and columns,while there is no requirement for angle steel connections and T-joints,which greatly limits the development of semi-rigid joints.This paper mainly studies the double web-top and bottom angle semi-rigid beam-column connections in beam-to-column angle steel connections.Referring to some approximate treatment methods in current codes at home and abroad,the theoretical analysis of the joints is carried out,and the mechanical properties of angle steel components are analyzed by using finite element software ABAQUS.Firstly,the effective force components in the joint area of double web-top and bottom angle semi-rigid beam-column connections are separated by using the method of end-to-end plate connections(component method)in Eurocode 3.The mechanical characteristics of the effective components are analyzed,and the mechanical parameters(stiffness and bearing capacity)of each component are determined.The spring model expression is used to replace each component,and the spring model is introduced.By combining rows,the mechanical calculation model is obtained,and the formula for calculating the initial rotation stiffness of the nodal region is derived.Secondly,the finite element analysis software ABAQUS is used to model the double web-top and bottom angle semi-rigid beam-to-column connections.The results of the finite element model are compared with those of the theoretical derivation to verify the correctness of the theoretical formula A large number of models of angle steel components are built by using finite element analysis software ABAQUS.The effects of various parameters on the initial tensile stiffness and load-carrying capacity of angle steel are studied.Then a simplified formula for calculating the diversion coefficient of angle steel forces with stiffeners is established.The main innovations of this paper are as follows:1.A simplified formula for calculating the rotational stiffness of semi-rigid beam-to-column connections with double web and top-bottom angle without stiffeners is derived by using the modified component method,and the corresponding mechanical calculation model is established.2.The finite element analysis software ABAQUS is used to model the semi-rigid beam-to-column connections with double web-top and bottom angle steel.The effects of three parameters,i.e.,bolt pretension,angle steel stiffener and column web stiffener,on the initial rotation stiffness and load-bearing capacity of the semi-rigid beam-to-column connections with double web-top and bottom angle steel are analyzed.3.Using finite element analysis software ABAQUS,120 sets of angle steel with and without stiffeners were modeled.The four parameters of angle steel triangular stiffener length-height ratio,bolt-to-stiffener height ratio,cross-sectional area ratio of tension angle plate to stiffener cross-sectional area ratio,side-by-side bolt pitch-to-stiffener thickness ratio were analyzed.The influence of mechanical properties of non-stiffened ribbed angle steel members is investigated,and the simplified formula for calculating the stiffness conversion coefficient between stiffened ribs and non-stiffened ribs of angle steel strips is fitted,that is,the simplified formula for calculating the force diversion coefficient.4.The influence of the shape of the bolt stiffening rib of angle steel model,the distance between the bolt on the bending angle plate and the pulling angle plate,and the parameter change of the angle steel side-by-side bolt distance on the initial tensile stiffness and load-bearing capacity of angle steel are analyzed,and the optimum range of these parameters is summarized. |
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